There are specialized .exe packers/compressors for 64k intros (more tuned than UPX) such as http://www.farbrausch.de/~fg/kkrunchy/ http://www.farbrausch.de/~fg/

There are specialized .exe packers/compressors for 64k intros (more tuned than UPX) such as http://www.farbrausch.de/~fg/kkrunchy/ http://www.farbrausch.de/~fg/kkrunchy/ I think one of the biggest challenges, size-wise, is coming up with good algorithms for procedural content (textures, 3d meshes, camera paths, audio/synths). Code for audio playback and for doing directx/opengl scene rendering shouldn't be too hard to keep small, but you really need to work to get interesting content to fit, since you can't really include much in the way of of bitmaps/audio samples/3d meshes as binary data assets.