The current release version is missing the trunc_sat instructions. It looks like a [commit](https://github.com/xtuc/webassemblyjs/commit/af8e766c26d36c34c3b84c975d3dea96dcf22197) has been already been made for this, but not a release. FWIW, the parser no longer works with the default output of emscripten because of this.