Um I think at a gear shop
Chat with our AI personalities
http://m0006.gamecopyworld.com/games/pc_sonic_heroes.shtml#Sonic%20Heroes%20MEMORY%20EDITOR
While I'm pretty low on memory, you need to find it within a mission stage.
you can it find by :pgm
Go on google and type in sonic spritesit will then say under sonic sprites the mysticalforest=)well if you go to the mysticleforestzone.com you can find sprites for just about any sonic character you can think of
There isn't a full version you download from the internet, but you can download the ps2 emulator and then find the download site for zero gravity. It isn't that great on the emulator but that's the only way to get it on your PC. also there's a wii emulater to play it on