In Contra there are various enemies, each enemy type is assigned a number. Enemy types whose number is larger than #$0f are level specific.
For outdoor levels, each enemy has 3 bits available to modify their attributes in some way. For indoor/base levels, and generated enemies, each enemy has an entire byte for their attributes. This page documents this data as well.
For some enemies, the last bit of the Y position also serves as bit 3 of the attributes. An odd Y position will make bit 3 of attributes set, and an even Y position will make bit 3 of attributes clear. Examples include the pill box sensor (common), and the claw (hangar).
These enemies are shared and can be used among all levels.
Gives the player various power-ups/weapons upgrades. It is a letter representing the weapon type surrounded by wings.
ENEMY HP: n/a
- Rapid Fire (R) -
- Machine Gun (M) -
- Flame Thrower (F) -
- Spray Gun (S) -
- Laser (L) -
- Barrier (B) -
- Falcon -
000- Rapid Fire (R) - Modifier that speeds up the bullet velocity of all weapons with the exception of the laser rifle.001- Machine Gun (M) - On-screen capacity of six bullets, which are faster than the default weapon.010- Flame Thrower/Fire Gun/Fire Ball (F) - Small fireball that moves forward in a winding pattern, making small loops. It has an on-screen capacity of four fireballs.011- Spray Gun/Spread Gun (S) - Fires several bullets in a wide arc, with an on-screen capacity of ten bullets. Each bullet is as powerful as a machine gun bullet.100- Laser (L) - The most powerful weapon per shot, but also the slowest. This drawback is mitigated by the fact that the beam will continue to pass through defeated enemies, so you can take out an entire line of them in one shot.101- Invincibility/Barrier (B) - Modifier that protects from anything (except falling in pits) for about twenty seconds. Any infantry that touches the player will be instantly killed, but vehicles and heavy guns will be unaffected.110- Falcon - destroys every basic enemy on the screen. It does little to no damage to vehicles, artillery, and other machines. Also known as Mega Shell, Mass Destruction, or Eagle Weapon111- Unused same as110, but no flying capsule is visible at all
ENEMY_VAR_1for indoor levels, stores initial y positionENEMY_VAR_Bis the vertical velocity coefficient for indoor arcs when falling towards the player. Negative goes up, positive goes down.
This enemy type is generated by various enemies and not be used alone. If used alone in a level, a single immobile bullet will be rendered. Attributes are not used for this enemy type.
ENEMY HP: n/a
- Regular Bullet -
- Red Regular Bullet -
- Cannonball/Tomato -
- Level 3 Dragon Fire Ball -
ENEMY_VAR_1specifies the bullet type
| Bullet Type | Description | Sprite | Palette | Collision Code |
|---|---|---|---|---|
| #$00 | regular bullet | sprite_1e | #$01 | #$01 |
| #$00 (snow field) | red regular bullet (see bullet type #$05) | sprite_07 | #$02 | #$01 |
| #$01 | level 1 boss large cannonball | sprite_21 | #$02 | #$05 |
| #$02 | indoor large cannonball (boss screen) | sprite_21 | #$02 | #$05 |
| #$03 | indoor regular bullet | sprite_1e | #$01 | #$01 |
| #$04 | level 3 dragon boss fire ball | sprite_79 | #$01 | #$02 |
| #$05 (snow field) | #$00 override (see enemy_bullet_routine_01) |
sprite_07 | #$02 | #$00 |
Bullet types #$01 and #$02 are sometimes colloquially referred to as tomatoes.
Other Names: Weapon Box
Creates 'Weapon Items' when destroyed
ENEMY HP: 1 when open, invincible when closed
For the 3 attribute bits, this enemy uses the same attributes as the 'Weapon Item' enemy type. Unlike most enemies, this enemy's least significant bit of the vertical position is also used to specify which tile is shown after being destroyed.
Other Names: Weapon Zeppelin, Power-Up Capsule, Weapon Wings, Weapon Drop, Flying Item Pod, or Football
Weapon Item transportation device that which travels from the left end of the screen to the other in a wave-like pattern.
ENEMY HP: 1
The flying capsule enemy type uses the same attributes as the 'Weapon Item' enemy type.
ENEMY_VAR_2
Other Names: Gray Turret, Rotating Turret
Shoots in 360 direction.
ENEMY HP: 8
Only least 2 significant bits are used for attributes
000- 1 bullet per attack001- 2 bullets per attack010- 3 bullets per attack011- 3 bullets per attack
ENEMY_VAR_1- [#$00-#$0b] aim direction starting #$00 facing right incrementing clockwise, e.g. #$06 is facing leftENEMY_VAR_2- bullets per attackENEMY_FRAME- super-tile to draw, not a sprite. Relative offset intolevel_1_nametable_update_supertile_data, orlevel_3_nametable_update_supertile_data.
Other Names: Running Man
A soldier that can move to attack
ENEMY HP: 1
.... ...x- running direction - 0 is left, 1 is right.... ..x.- whether the soldier turns around on edges, set means to turn around once soldier reaches edge, clear means to walk off edge. Soldiers will only turn around a maximum of #$02 times.... .x..- whether or not the enemy shoots bullets.xxx ....- initial animation delay offset (soldier_initial_anim_delay_tbl)
ENEMY_VAR_1- soldier fire recoil timerENEMY_VAR_2- soldier x direction #$00 is left, #$01 is rightENEMY_VAR_3soldier_routine_02- whether or not the soldier is jumpingsoldier_routine_03- track number of bullets to soldier will fire
ENEMY_VAR_4- the number of times the soldier has changed directionsENEMY_VAR_A- controls which sprite to load, causes sprite to increment every #$08 frames runningENEMY_FRAME- sprite to draw. Offset intosoldier_sprite_codes
Soldiers can be randomly generated based on a formula
- How many times the player has beat the game
- What is the player's current weapon strength
- Which level they are on
Other Names: Ledder, Rifle Man
Stand in place and can fire in any direction
ENEMY HP: 1
.... .xxx- sniper type/behavior.... .000- stands and shoots bullets three at a time.... .001- crouch (hide) and shoot one bullet at a time.... .010- crouch (hide) and shoot bullets three at a time (boss screen sniper).
ENEMY_VAR_2- sniper firing angleENEMY_VAR_3- set to #$06 when sniper is firingENEMY_VAR_4- The number of bullets to fire (seesniper_bullet_attack_count_tbl)ENEMY_FRAME- sprite to draw. Offset intosniper_sprite_00for sniper types #$00 and #$01,sniper_sprite_01for sniper type #$04 (boss screen sniper)
Other values for the attribute yield unpredictable results
Other Names: Gulcan, Cannon
Rises from the ground and shoots at the player. Once past by the players, and scrolled enough to the edge of the screen, goes back into the ground.
ENEMY HP: 8
Only least significant bit is used
000- Rocky background001- Forrest background
ENEMY_VAR_1- bullet initial x, y offsets (#$6 bytes)
Other Names: Triple Turret, Triple Cannon, Gelguge, Zark Turret
Exists only in the indoor (base) levels. Shielded turrets.
No attributes exist for this enemy.
ENEMY HP: 8
ENEMY_VAR_1- HP
Other Names: Shoud
Indoor boss screen shielded cores
ENEMY HP: 10
Generated by the scuba diver (enemy type #$0c) in waterfall level and ice field levels. Also generated by mortar launcher (enemy type #$17) on hangar zone boss screen. These enemies generate a single mortar shot, but once the mortar shot reaches its vertical apex, 3 other mortar shots are generated. The original mortar shot becomes an explosion.
ENEMY HP: n/a
.... ..xx- mortar shot type [#$00-#$04].000- initial mortar shot. Travels straight up quickly001- middle of the 3 split mortar shots. Travels straight up small amount010- right of the 3 split mortar shots.011- left of the 3 split mortar shots.
ENEMY_VAR_1- [#$01-#$04] when non-zero specifies the direction of the initial mortar shot, starting at the 4th entry ofmortar_shot_velocity_tbl. The split mortar shots are always from theENEMY_ATTRIBUTES. Used on the hangar zone boss screen by the Mortar Launcher (#$17) to aim mortar shots.
Other Names: Acuba
A soldier hiding in water until activated, then fires mortar shots (enemy type #$0b).
ENEMY HP: 1
No attributes exist for this enemy.
ENEMY_VAR_1- stores recoil timer before firing mortar shot
Other Names: Turret Man, Mounted Soldier
ENEMY HP: 10
.... ..xx- delay between shots. Actual delay is this value multiplied by 16 and then 1 is added.
Other Names: Turret Man Bullet
ENEMY HP: n/a
There are 3 enemies that are specific to Level 1 - Jungle.
Other Names: Blaster Cannon, Repeater Cannon, Destroi, Dikembe turret
One of 2 cannons on the Jungle level boss defense wall. Shoots projectiles that fall in an arching motion.
ENEMY HP: 16
Only least significant bit is used
000- Wall background001- Black (Jungle) background
The wall background is used for the bomb turret closest to the screen so it is part of the defense wall. The black background is used on the other bomb turret and matches the black background.
Other Names: Wall Plated Door, Boss Wall Plated Door, Dikembe
The target shot on the Jungle level boss defense wall. When shown it causes a quick siren sound to play. It does not fire back and has an initial health of 0x20 the first time you play the game.
ENEMY HP: 32
No attributes exist for this enemy.
There are two bridges throughout level 1 that explode as the players cross them. The bridge is 4 super-tiles wide and explodes as the players cross it.
ENEMY HP: n/a
They are no attributes for this enemy type.
ENEMY_VAR_1- the current bridge section being exploded, goes from #$00 to #$03. Once #$04 is encountered, the bridge is removed.ENEMY_VAR_2- the current number of the small sprite explosion. #$03 small explosions happen before the generic explosion animation begins. Each section follows the same pattern: #$03 small explosions, then the generic explosion.
The animation for the bridge explosion happens section by section with the first
section being a little different. In general, when a section starts exploding,
the nametable super-tile is updated for the previous bridge section, and the
first mini-explosion cloud is drawn. On the next animation (#$04 frames later),
the current bridge section is updated to its second super-tile value and the
second mini-cloud created. After an addition #$04 frames, the 3rd cloud is
drawn with no super-tile changed. Once the third mini-explosion is created,
the routine is updated to exploding_bridge_routine_04 to move to the next
bridge section. This loop continues until all sections are exploded. The first
section is special in that there is no previous bridge section to update. The
last section is special in that it only has 1 super-tile animation.
Other Names: Garmakilma, Boss Fire Eye
Boss for level 2.
ENEMY HP: 16
Uses ENEMY_VAR_1 to track HP. ENEMY_HP is set to 1 so that the enemy
destroyed routine can play a metal ting sound (sound_16) every collision.
ENEMY_VAR_1- Boss Eye's real HP
Other Names: Darr, Rolling Grenade
ENEMY HP: 5
Other Names: Hand Grenade
Grenades are thrown by indoor soldiers (15) and grenade launchers (17) on indoor levels.
ENEMY HP: n/a
No attributes exist for this enemy.
ENEMY_VAR_1- grenade y positionENEMY_VAR_2- used in calculating falling arc positionENEMY_VAR_3- used in calculating falling arc positionENEMY_VAR_4- used in calculating falling arc positionENEMY_VAR_B- used in calculating falling arc positionENEMY_FRAME- sprite to draw. Offset intogrenade_sprite_codes_00,grenade_sprite_codes_01, orgrenade_sprite_codes_02
Similar to #$08 Wall Cannon. Exists only in the indoor (base) levels.
ENEMY HP: 4
.... ..xx- initial wall turret animation delay (offset intowall_turret_initial_delay_tbl)
ENEMY_VAR_1- used to know if closed wall turret super-tile has been drawnENEMY_FRAME- offset intowall_turret_tile_animation_tbl, which offsetslevel_2_4_tile_animation
Other Names: Wall Core, Shoud, Sensor
An energy core target on indoor/base levels. Don't attack until 7 rounds of attack from generated soldiers have happened. Destroying all of this enemy type allows advancement to next screen by disabling the electric fence. These enemies have an delay before opening. Before opening, they are not able to be attacked. Cores can be 'plated', meaning there is a protective wall that must be destroyed before you can attack the core directly.
ENEMY HP: 8 or 16 (big core)
.... x...- Big Core.... .x..- Plated (0 = not plated, 1 = plated).... ..xx- Opening Delay - index intocore_opening_delay
Opening delay is not used if the core is plated. Instead a default delay of #$20 is used.
ENEMY_VAR_A- bullet collision sound codeENEMY_VAR_1- ensure wall core nametable is updatedENEMY_VAR_2- index intolevel_2_4_tile_animationspecifying nametable tiles to update (seewall_core_tile_anim_tbl)ENEMY_VAR_3- after wall cores are all destroyed, the back wall is destroyed as well. This variable tracks which destroyed back wall portion to draw
Other Names: Running Soldier, Running Guy
Runs from one side of the screen to the other
ENEMY HP: 1
... ..xx.- weapon type (00 = shoot, 01 = grenades, 10 and 11 = drop rollers).... ...x- direction (0 = from right, 1 = from left)
Other Names: Jumping Guy, Jumping Guy
Travels across the screen while jumping
ENEMY HP: 1
...x xx..- weapon type.... ..x.- soldier will be red in second enemy cycle (drop rapid fire weapon item).... ...x- direction (0 = from right, 1 = from left)
ENEMY_VAR_1- y velocity index. Offset intojumping_soldier_y_vel_tbl
Other Names: Seeking Guy
Launches bomb grenades at user
ENEMY HP: 1
.... ...x- direction (0 = from right, 1 = from left).... .xx.- number of grenades per attack
ENEMY_VAR_1- number of grenades to fireENEMY_VAR_2- closest player index to grenade launcherENEMY_VAR_3
Other Names: Soldier Squad
Always created in groups of 4 that act as one enemy. All 4 soldiers come in from one side of the screen, stop in middle to fire at the player, then split up into 2 groups going in opposite directions. Then the 2 groups fire again at the player, and finally they walk off screen.
ENEMY HP: 1
.... ...x- direction (0 = from right, 1 = from left)
ENEMY_VAR_1- the individual number of the soldier within the group of four soldiers, i.e. #$00 to #$03ENEMY_VAR_2- number of times soldier has stopped to fire at the player. The maximum is #$02.
Other Names: Green Soldier Generator
Generates soldiers depending on the whether level 2 or level 4 and the level screen number. Is able to generate #$04 different enemy types.
- #$15 - Indoor Soldier
- #$16 - Jumping Soldier
- #$17 - Grenade Launcher
- #$18 - Group of Four Soldiers
ENEMY HP: n/a
.... ...x- level number, 0 = level 2, 1 = level 4
ENEMY_VAR_1- used to keep track of which enemy to generate on the current screen.
Creates roller enemies (#$11).
ENEMY HP: n/a
.... .xxx- offset intoroller_gen_init_tbl- #$00 -
roller_gen_init_00 - #$02 -
roller_gen_init_01
- #$00 -
Other Names: Sphere Projectile, Eye Projectile, Ring of Fire
Fire ring emitted from #$10 Boss Eye (Garmakilma).
ENEMY HP: 2
Other Names: Boss Gemini, Boss Metal Helmet
ENEMY HP: 10
No attributes exist for this enemy.
The health of the boss gemini helmets are #$01 and each hit 'destroys' them.
However, the destroyed routine boss_gemini_routine_03 will check ENEMY_VAR_4
for the boss gemini helmet's actual HP.
Note that this enemy uses ENEMY_Y_VELOCITY_FRACT and ENEMY_Y_VELOCITY_FAST
not for anything with the y velocity, but rather to control speed of x movement
and keep track of x distance from initial position respectively.
ENEMY_FRAME- offset intoboss_gemini_sprite_tbl, which contains the exact sprite code:sprite_68,sprite_69,sprite_6a,sprite_6b,sprite_6c.ENEMY_VAR_1- initial x positionENEMY_VAR_2- timer after being hit - #$10 down to #$00ENEMY_VAR_3- whether or not the boss gemini's health is low (less than #$07). Used to show a red brain instead of a green one.ENEMY_VAR_4- actual representation of ENEMY_HP, initialized to #$0aENEMY_X_VELOCITY_FRACT- always #$80 (.50). Used withENEMY_Y_VELOCITY_FRACTto move gemini by 1 every #$02 framesENEMY_X_VELOCITY_FAST- x direction of boss gemini- #$00 - boss gemini are traveling away from center
- #$ff - boss gemini are traveling towards center
ENEMY_Y_VELOCITY_FRACT- alternates every frame between #$00 and #$80. Used withENEMY_Y_VELOCITY_FRACTto move gemini by 1 every #$02 framesENEMY_Y_VELOCITY_FAST- offset from initial x position. Either added to or subtractedENEMY_VAR_1based on whether the frame is even or odd. Goes from #$00 to #$30ENEMY_HP- always #$01 until hit by bullet. The 'enemy destroyed' routine will resetENEMY_HPback to #$01 untilENEMY_VAR_4is #$00.ENEMY_ANIMATION_DELAY- how long for the helmet to stay still when merged, or when farthest distance apart. The value is set to #$20 in game for when farthest apart, and #$30 when merged. If the helmets are moving (either toward each other or away), the value will be #$00.
Other Names: Spinning Bubbles
Red and blue molecule-like orbs that are created by #$1c Boss Gemini (Godomuga). They seek the player for a determined amount of time. If after set number of seeks (#$13), then the bubble pair will continue in last direction.
ENEMY HP: 1
.... .xxx- specifies how frequently the bubbles will spin. Initialized inspinning_bubbles_routine_00to a random value between 0 and 3 inclusively. Value is an offset intospinning_bullet_spin_tbl.
ENEMY_VAR_1- enemy aim direction, offset intospinning_bullet_vel_tblENEMY_VAR_2- closest player to spinning bubbleENEMY_VAR_3- number of times that the spinning bubble has checked to see if it should readjust its aiming direction, after #$13 checks, the bubble will stop targeting player and continue in last direction.ENEMY_FRAME- #$6d is added to this value to get actual sprite codesprite_6d,sprite_6e,sprite_6f,sprite_70,sprite_71,sprite_72
Other Names: Blue Jumping Guy, Boss Blue Soldier, Blue Soldier, Birdman
ENEMY HP: 1
.... ..xx- specifies initial position (seered_blue_soldier_init_pos_tbl) and initial x velocity (seered_blue_soldier_init_vel_tbl). When bit 0 is clear, the blue soldier is coming from the right. When bit 0 is set, the blue soldier is coming from the left.
ENEMY_FRAMEblue_soldier_routine_01- offset fromsprite_85up tosprite_87. Used to animate running horizontally.blue_soldier_routine_02- offset fromsprite_88up tosprite_8a. Used to animate jumping down to attack.blue_soldier_routine_03-ENEMY_FRAMEis not used, ratherENEMY_SPRITEis updated directly to eithersprite_8aorsprite_8b
Other Names: Red Shooting Guy, Boss Red Soldier, Red Soldier
ENEMY HP: 1
.... ..xx- specifies initial position (seered_blue_soldier_init_pos_tbl) and initial x velocity (seered_blue_soldier_init_vel_tbl). When bit 0 is clear, the red soldier is coming from the right. When bit 0 is set, the red soldier is coming from the left. When bit 1 is clear, the horizontal distance between the player and the enemy before attacking is #$10 pixels. Otherwise, the distance is #$30 pixels.
ENEMY_VAR_1- number of bullets to fire per roundENEMY_VAR_2- whether or not the red soldier has fired at the player. Used to ensure red soldier only fires once, then runs off screen.ENEMY_FRAME- offset fromsprite_8c, goes up tosprite_90.
Other Names: Red Blue Soldier Generator
ENEMY HP: n/a
Generates Garth and Rangel enemies following a pattern specified in
red_blue_solider_data_tbl.
- red soldier (x4), #$a0 delay
- blue soldier (x2), #$40 delay
- blue soldier (x2), #$80 delay
- red soldier (x2), #$60 delay
- red soldier (x4), #$a0 delay
- blue soldier (x4), #$a0 delay
- red soldier (x4), #$fc delay
No attributes exist for this enemy.
ENEMY_VAR_1- the read offset into the table specifying the red and blue soldiers generation behavior. After all the soldiers are generated (based onred_blue_solider_data_tbl), then the number is reset and the soldier generation pattern is repeated.
Floats back and forth to allow players to jump higher in level. This enemy is very similar to the moving flame enemy, which is also in the vertical level.
ENEMY HP: n/a
000- platform starts out moving left at 1 unit per frame001- platform starts out moving right at .75 units per frame on average
Flame that goes back and forth over bridge. This enemy is very similar to the floating rock platform enemy, which is also in the vertical level
ENEMY HP: n/a
010- Flame starts out moving left at 1 unit per frame011- Flame starts out moving right at 1 unit per frame
Generates #13 Falling Rocks
ENEMY HP: n/a
Other Names: Boulder
ENEMY HP: n/a
ENEMY_VAR_1- y position of most recent ground collision
Other Names: Boss Mouth, Gromaides
ENEMY HP: 32
ENEMY_VAR_1- dragon HP, used to keep track of HP between opening and closing of mouthENEMY_VAR_2- when dragon destroyed, keeps track of current explosion to drawENEMY_VAR_3- used inboss_mouth_routine_08to ensure the that the enemy destroying animation starts on second execution ofboss_mouth_routine_08and not the first
Other Names: Boss Arm, Boss Tentacle, Dragon Arm, Dragon Arm Orb
5 of these enemies exist on each tentacle of the Dragon. Level specifies 2, one for each arm. Each side then spawns 4 additional dragon arm orb enemies. Loops through 5 different attack patterns. This is the most complicated enemy in the game.
ENEMY HP: 16
.... ...x- dragon arm orb side- 0 - right side of screen (dragon's left arm)
- 1 - left side of screen (dragon's right arm)
To simplify understanding, I've named some some of the parts of the arm.
- shoulder - the 2 'parent' orbs that are specified in the enemy level screens. The shoulder orbs generate/spawn the rest of the arm orbs (enemy type #$15). These are the two orbs on either side of the dragon that are closest to the body
- hand - the red orb at the end of the arm. This is the only orb with collision enabled. These are the two orbs on either side of the dragon that are farthest from the body.
Below is an example ASCII drawing of enemy slot index for each dragon arm orb to simplify defining the enemy vars.
#$06 $08 $0d $0f $0c (o) MMM (o) $0b $0e $09 $07 $0f
ENEMY_X_VELOCITY_FRACT- dragon arm orb shoulder value specifies the 'angle' and other orbs specify how curled for the arm to be- shoulder -
ENEMY_X_VELOCITY_FRACTis set to equalENEMY_VAR_1. This value is an absolute index intodragon_arm_orb_pos_tbl - all other orbs - the running total of index into
dragon_arm_orb_pos_tbl. Each farther orb has the next value. Then the orb'sENEMY_VAR_1is added to get position.
- shoulder -
ENEMY_VAR_1- used in correlation with shoulder'sENEMY_X_VELOCITY_FRACTto set position.ENEMY_VAR_1is the distance from the previous orb's position index.ENEMY_VAR_2- duration timer for rotation direction. positive = clockwise, negative = counterclockwiseENEMY_VAR_3- specifies the next dragon arm orb enemy slot index, e.g. dragon arm orb enemy slot #$0c will haveENEMY_VAR_3set to #$0f, which is the next farther dragon arm orb in the dragon's arm (see ascii diagram above). The last orb in the arm (the hand) (#$06 and #$0f) will have a value of #$ff.ENEMY_VAR_4- specifies the previous dragon arm orb enemy slot index, e.g. dragon arm orb enemy slot #$07 will haveENEMY_VAR_4set to #$09, which is the previous dragon arm orb in the dragon's arm (closer to the body) (see ascii diagram above). The first orb in the arm (the shoulder) will have a value of #$ff.ENEMY_VAR_A- used by shoulder orbs as a timer for firing dragon boss fire balls from arms.ENEMY_FRAME- indragon_arm_orb_routine_01, used to keep track of remaining boss arms to spawn. Once child dragon arm orbs are created, then used on parent dragon arm orb only to specify attack pattern behavior. Unlike, most other enemies,ENEMY_FRAMEis not actually used to determine any sprite codes, tiles, nor super-tiles.- #$00 - wave arm up and down
- #$01 - spin toward center
- #$02 - spin away from center
- #$03 - hook shape
- #$04 - arm seeking player, reaching down
No attributes exist for this enemy.
ENEMY HP: n/a
ENEMY HP: n/a
No attributes exist for this enemy.
ENEMY_FRAME- value modulus #$03 offset intoice_grenade_sprite_tbl
Other Names: Dogra
ENEMY HP: 71
.... ...x- tank attack delay index intotank_attack_delay_tbl
ENEMY_VAR_1- tank super-tile aim direction, used also to load correct tank turret super-tile.- #$0c = straight left
- #$0b = aiming down left
- #$0a = down down left
ENEMY_VAR_3- remaining bullets to fire when stopped in current round of attack before re-aiming. Starts at #$03 and goes to #$00 during attack phase repeatedly untilENEMY_VAR_4elapsed.ENEMY_VAR_4- timer before stopped tank continues advancingENEMY_X_VEL_ACCUM- whether or not the tank is on the screen- #$01 - off screen to the right
- #$00 - visible on screen
- #$ff - off screen to the left (starts when first wheel is off screen)
Other Names: Pipe Joint, Ice Joint
ENEMY HP: n/a
No attributes exist for this enemy.
Other Names: Guldaf, Boss UFO
ENEMY HP: 32
No attributes exist for this enemy.
Appears randomly and creates flying saucers (enemy type - #$15) and drop bombs
(enemy type - #$16). One of the few enemies that use BG_PALETTE_ADJ_TIMER to
create a fading in effect.
ENEMY_VAR_1- used when drawing to know which super-tile to draw, and where to draw explosions when boss ufo is destroyedENEMY_ANIMATION_DELAY- used as an index to know which part of the boss ufo to update, [#$00-#$03]. Indexes intoboss_ufo_supertile_pos_tbl
Other Names: Mini UFO
ENEMY HP: 1
No attributes exist for this enemy. Direction of flying saucer is determined by Alien Carrier.
Bombs dropped from the Alien Carrier
ENEMY HP: 1
Other Names: Energy Beam
These 3 enemy types are very similar. They differ in the direction they fire
- #$10 - down
- #$11 - left
- #$12 - right
Horizontal fire beams have randomness baked into the duration after receding to then re-ignite. They do not wait for player proximity either compared to the vertical fire beams.
.... ..xx- beam length code (0-3) (index, not actual amount).... xx..- beam delay between bursts (index intofire_beam_anim_delay_tbl)- 00 = #$00
- 01 = #$20
- 10 = #$40
- 11 = #$60
xx.. ....- collision code logic, seecollision_code_f, offset intocollision_code_f_adj_tbl(0, 4, 8, or 16)
ENEMY_VAR_A- beam delay between burstsENEMY_VAR_2- fire beam length before for both horizontal and downward fire beams before moving to eitherENEMY_VAR_3orENEMY_VAR_4depending on specific fire beam typeENEMY_VAR_3- horizontal fire beam lengthENEMY_VAR_4- vertical fire beam length
Other Names: Gordea, JJ, Jumping Joey, Jumping Jack Flash, Giant Boss Robot, Giant Armored Soldier, Boss Giant
ENEMY HP:
(PLAYER_WEAPON_STRENGTH * #$08) + #$40
| Weapon | Strength | HP |
|---|---|---|
| Default | 0 | 64 |
| M | 2 | 80 |
| F | 1 | 72 |
| S | 3 | 88 |
| L | 2 | 80 |
No attributes exist for this enemy. His health is calculated based on player's
PLAYER_WEAPON_STRENGTH value. The formula is below
ENEMY_VAR_1- random number used to control boss action: jump, attack, nothing. For routines #$06 and #$07, used to specify current explosion number. Forboss_giant_soldier_routine_09used to animate door opening.ENEMY_VAR_2- delay between steps
- y position of door when opening
ENEMY_VAR_3- delay timer between sections of the door before openingENEMY_VAR_4- number of consecutive thrown saucersENEMY_HP- (PLAYER_WEAPON_STRENGTH* #$08) + #$40
Other Names: Saucer, Spiked Disk Projectile
ENEMY_VAR_1- bit 0 specifies sprite code offset from #$bb, i.e.sprite_bb, orsprite_bc. Increments after every animation delay has elapsed.
Other Names: Moving Claw
ENEMY HP: n/a
Mechanical claw similar to arcade claw machines
xx..- high two bits specify at which frame counter number to begin descending, linked toclaw_frame_trigger_tbl. Afterclaw_routine_00, these two bits are stripped away from the attributes...xx- during initialization inclaw_routine_00, these 2 bits specify the claw length code, linked toclaw_length_tbl- claw length code #$03 (
11) also specifies that the claw is a 'seeking' claw and will attack when the player is near.
- claw length code #$03 (
ENEMY_VAR_2- renaming iterations of extension when ascending. #$00 for fully extended and when descendingENEMY_VAR_3- current length of claw, #$ff for fully retracted clawENEMY_VAR_4- offset intoclaw_update_nametable_ptr_tblENEMY_FRAME- stores the frame counter number at which the claw descendsENEMY_ATTRIBUTES. Unlike other enemy types, it doesn't store graphic information.
Other Names: Spiked Wall
A spiked wall that rises from the ground in front of the player
ENEMY HP: 16
.... ..xx- bits 0 and 1 are an index intorising_spike_wall_delay_tbl, which specify how long to delay (in frames) before rising once the player has gotten close to the spiked wall location..... xx..- bits 2 and 3 are an index intorising_spike_wall_trigger_dist_tbl, which specify how close the player has to be to the wall before it is 'activated'
Note that bit 6 and 7 of ENEMY_ATTRIBUTES are both set to 1 during the first
routine. This is to allow adjusting the collision box to grow upward with the
rising spiked wall by using offset 16 into collision_code_f_adj_tbl.
ENEMY_VAR_1- used for dynamic collision box size logic (seeset_enemy_collision_box)ENEMY_VAR_2- used to initialize wall super-tiles, offset intorising_spiked_wall_data_tblENEMY_VAR_3- used to store the distance the closest player has to be before the wall will start rising delay timer (ENEMY_VAR_4).ENEMY_VAR_4- the delay that controls when the wall will start rising. This delay timer is started once the closest player gets within a certain range of the wall
Similar to Rising Spiked Wall (#$11), but taller and stationary
ENEMY HP: 16
.... ..xx- index intospiked_wall_destroyed_data_tbl- #$00 - small spiked wall that is half of the screen on a platform
- #$02 - larger spiked wall that is about 3/4 of the screen
Note that bit 6 and 7 of ENEMY_ATTRIBUTES are both set to 1 during the first
routine. This is to allow adjusting the collision box to grow upward with the
rising spiked wall by using offset 16 into collision_code_f_adj_tbl.
ENEMY_VAR_1- used for dynamic collision box size logic (seeset_enemy_collision_box)
Other Names: Mine Cart Generator
ENEMY HP: n/a
Other Names: Moving Cart
Moving mining cart that can be destroyed.
ENEMY HP: 3
This enemy is only ever created by #$13 (Mining Cart Generator), so enemy attributes are encoded in code during generation.
- #$80 - the cart should be destroyed when colliding with background
- bit 7 0 - specifies the cart should reverse direction after collision with background
Other Names: Immobile Cart
Stationary mining cart that can start moving when a player lands on it
ENEMY HP: 3
- #$80 - the cart should be destroyed when colliding with background (only used for generated moving carts and not stationary carts)
- bit 7 0 - specifies the cart should reverse direction after collision with background
Other Names: Armored Door With Siren
ENEMY HP: 32
Other Names: Boss Mortar
Launches mortar shots (enemy type #$0b) on the boss screen.
ENEMY HP: 8
...x- initial attack delay. bit 0 set is a #$10 delay, bit 0 clear is a #$60 delay.
ENEMY_VAR_1- direction of generated launched mortar shot. After creating mortar shot, the launcher updates the mortar shot'sENEMY_VAR_1to match launcher's value. Ultimately, is used as offset intomortar_shot_velocity_tbl.ENEMY_FRAME- relative offset intolevel_7_tile_animation, to get real offset add #$08 to this value.
Other Names: Boss Soldier Generator, Enemy Generator
Generates waves of soldiers on the hangar boss screen. Stops generating soldiers once both mortar launchers (enemy type #$17) are destroyed or 30 waves of soldier attacks have occurred. Soldiers are generated on either side of the screen depending on players' location. To make things more challenging, once one mortar launcher is destroyed, or if 20 waves of soldier attack have occurred, then even if the player is close to the left side, soldiers will randomly be generated on the left side.
ENEMY HP: n/a
ENEMY_VAR_1- number of soldiers to generate for current attack waveENEMY_VAR_2- facing direction of the soldiers to generate- 0 - left (comes from right side of screen)
- 1 - right (comes from left side of screen)
ENEMY_VAR_3- number of waves of soldiers generatedENEMY_FRAME- offset intoboss_soldier_nametable_update_tbl, which referenceslevel_7_nametable_update_supertile_data. Specifies the the super-tiles to update for the opening of the armored door to let soldiers advance.BOSS_SCREEN_ENEMIES_DESTROYED- number of destroyed mortar launchers. Used to know when to stop generating soldiers. The actual memory location is $85.
Other Names: Alien Guardian, Red Falcon (formerly), Alien Mini-Boss
Worm-like alien who generates bundles (enemy type #$11).
ENEMY HP:
HP = (PLAYER_WEAPON_STRENGTH * 16) + 55 + (GAME_COMPLETION_COUNT * 16)
Note if PLAYER_WEAPON_STRENGTH * 16 is larger than 255, then the results will
wrap around. So sometimes the HP is actually lower than a previous playthrough
where GAME_COMPLETION_COUNT was lower. This occurs every 16 loops. For more
details see Game Completion Modifier.md
ENEMY_VAR_1- super-tile code for mouth relative references to entries inlevel_8_nametable_update_supertile_dataalien_guardian_routine_04
ENEMY_VAR_2- whether or not the super-tiles were able to be drawnENEMY_VAR_3- whether or not the super-tiles were able to be drawnENEMY_VAR_4- delay between open mouth attacks
Other Names: Alien Fetus
ENEMY HP: Starts at 2
HP = GAME_COMPLETION_COUNT + 2
HP goes up by 1 every time the game is beaten (until max 255 due to memory limit where HP wraps back around). For more details see Game Completion Modifier.md
.... ...x- 1 - start enemy aim direction at #$18 (see
alien_fetus_routine_00)
- 1 - start enemy aim direction at #$18 (see
ENEMY_VAR_1- [#$00-#$0b] aim direction starting #$00 facing right incrementing clockwise. Every #$03 values causes a different sprite to show.ENEMY_VAR_2- whether or not the mouth is openENEMY_VAR_3- timer between re-aiming towards playeralien_fetus_aim_timer_tblENEMY_VAR_4- bit 0 specifies which player to aim at. Decremented by #$03 each time, so the targeted player changes.
Other Names: Alien Mouth
Generates Poisonous Insect Gel (enemy type #$13). Note that the wadder's mouth does not need to be open for it to generate poisonous insect gels.
ENEMY HP:
HP = (2 * GAME_COMPLETION_COUNT) + PLAYER_WEAPON_STRENGTH + 4
For more details see Game Completion Modifier.md
They are no attributes for this enemy type.
ENEMY_ANIMATION_DELAY- timer for generating poisonous insect gel creatures (enemy type #$13). This is a random number between #$1f and #$df inclusively.ENEMY_VAR_3- animation timer between updating super-tile. The mouth will be open for #$20 frames, then closed for #$20 frames.ENEMY_VAR_4- only bit 0 is used and it specifies which super-tile to draw, either mouth open or closed, seelevel_8_nametable_update_supertile_data.- #$00 = alien mouth closed
- #$01 = alien mouth open
Other Names: White Sentient Blob, White Blob, Cottonball, Cotton Ball
ENEMY HP: 1
They are no attributes for this enemy type.
ENEMY_VAR_1- aim direction of white blob [#$00-#$16]. #$00 is straight to the right (3 o'clock), increment clockwise until #$16, which is about 2 o'clock.ENEMY_VAR_2white_blob_routine_01random delay before moving to next routine, e.g. delay before freezing to then hone in on player. [#$50-#$6f]white_blob_routine_02- timer tracking current number of frames to keep the same velocity before retargeting the player
ENEMY_VAR_3- which player to attach (0 = p1, 1 = p2)ENEMY_VAR_4white_blob_routine_01- how many frames for the white blob to 'freeze' before attacking, either #$02 or #$22, seewhite_blob_set_freeze_length.white_blob_routine_02- how many frames to keep the same velocity before retargeting the player
ENEMY_ANIMATION_DELAY- interpreted as 2 nibbles- high nibble - timer for when to change to the next sprite. Sprite changes every #$08 frames
- low nibble - keeps track of
white_blob_spider_sprite_tblindex. Used to know which sprite to show next
Other Names: Alien Spider
ENEMY HP:
HP = PLAYER_WEAPON_STRENGTH + GAME_COMPLETION_COUNT + 2
For more details see Game Completion Modifier.md
This enemy's routine flow is different depending on how it was created. When
defined in the screen enemies data structure, alien_spider_routine_00 is the
first routine. When spawned by Eggron (enemy type #$15), the first routine is
alien_spider_routine_01.
graph TD
level_screen_enemy(level screen enemies) --> alien_spider_routine_00
alien_spider_routine_00 --> alien_spider_routine_03
alien_spider_routine_02 --> |egg spawns into spider|alien_spider_routine_03
alien_spider_routine_03 --> |spider jumps|alien_spider_routine_04
alien_spider_routine_04 --> |spider collides with ground/ceiling|alien_spider_routine_03
spawned_by_heart_boss(spawned by heart boss) --> alien_spider_routine_01
alien_spider_routine_01 --> alien_spider_routine_02
ENEMY_VAR_1- the player to attack. If two players, will attack either player 1 or player 2 randomly- #$00 - player 1
- #$01 - player 2
ENEMY_VAR_2- whether or not the alien spider will jump- #$00 - will not jump
- #$02 - will jump
ENEMY_VAR_3- y fast velocity of spiderENEMY_VAR_4- y fractional velocity of spider
Other Names: Spider Spawn, Cocoon
Enemy that appears with the final boss of the game, Gomeramos King. It produces buggers to defend the alien heart.
ENEMY HP:
HP = (GAME_COMPLETION_COUNT * 2) + (PLAYER_WEAPON_STRENGTH * 2) + 24
For more details see Game Completion Modifier.md
ENEMY_VAR_1- nametable update super-tile index to draw, all values have bit 7 set, indicating to not update the palette. Indexes intolevel_8_nametable_update_supertile_data. Used to animate spewing out an alien spider.ENEMY_VAR_3- frame number [#$00-#$02], used to keep track of which super-tile to draw. Directly correlates toENEMY_VAR_1.ENEMY_VAR_4- delay between generating alien spiders
Other Names: Alien Heart, Heart, Boss Heart
Gomeramos King is the final boss of the game. It is the beating heart of the Emperor Demon Dragon God Java.
ENEMY HP:
HP = (PLAYER_WEAPON_STRENGTH * 16) + 55 + (GAME_COMPLETION_COUNT * 16)
Note if PLAYER_WEAPON_STRENGTH * 16 is larger than 255, then the results will
wrap around. So sometimes the HP is actually lower than a previous playthrough
where GAME_COMPLETION_COUNT was lower. This occurs every 16 loops. For more
details see Game Completion Modifier
ENEMY_VAR_2- used to incrementENEMY_VAR_4ENEMY_VAR_4- used to specify super-tiles for heart beating animation