.GM81 File Extension
File TypeGame Maker 8.1 Project File
What is a GM81 file?
Project file created by GameMaker, a video game development application that enables games to be created using drag-and-drop actions; may include source code as well as references to game resources, such as graphics, sound effects, and music.
Once development is complete, GameMaker projects can be built into a standard Windows executable (.EXE) file.