Hey, thanks! That was exactly what I was looking for. The only link that I could find in the past was http://unhaut.fav.cc/retrun/ which doesn't seem to work
Was going to start modding my copy of Sonic CD today, and realized the download site for Return (The program needed to unpack and re-pack the game's .rsdk file) is down. Does anyone have a copy of the program they could put up on mediafire/dropbox/etc?