Sonic.exe 3.0 Source Code [better] -

// Load first level LevelLoader.LoadLevel("Level1");

While the original project is dead, the source code remains relevant for three reasons: SONIC.EXE 2.5 / 3.0 (CANCELLED BUILD) Explained in fnf sonic.exe 3.0 source code

containing new songs, characters, and assets that were intended for the final 3.0 update. Availability of the Source Code // Load first level LevelLoader