GameMaker 8 executables are split into two parts: a "runner" (virtualized by Windows) and a "gamedata" section. The gamedata contains all original assets, including: : Scripts and object events. : Sprites, sounds, backgrounds, and rooms.
An older tool designed for versions 5.3A through 7.0, sometimes tested with mixed results on GM8 files. 4. Security and Anti-Decompilation gamemaker 8 decompiler link
If you are the original author and lost your source code, decompilation is a lifesaver. GameMaker 8 executables are split into two parts: