They still had Spider-Man due to Sega having the license at the time, which they don't have now. Also it still used Sonny Chiba's digitized face from the intro to Shadow Warriors and I think the Godzilla boss was still Godzilla and not a skeleton. A fully infringement-fee version (which makes Spider-Man pink) didn't come out until the Wii Virtual Console/PS3/360 download. The latest Genesis collection was the first time it was included on a compilation though, maybe Sega doesn't think enough people like the game to include it.