Posts: 1,218
Threads: 13
Joined: May 2008
Looking around and it turns out that the PSP version of Project 8 and the Wii version of Proving Ground were done by the same developer. Page 44 Studios either forgot to remove them or just built Proving Ground on top of Project 8 by using the same engine/assets. Your filenames seem interesting since ngc means Gamecube but there was no Gamecube version of Project 8... (Either that or whatever they saved it as used that filename)
At least they are from the same game series so it was logical, some games have completely different assets from different games and even from different publishers/developers all together. Like prototype Mega Drive games for instance it was whatever was left on the cartridge that was used to write with and all sorts of random games were used. Someone even found sprites from a lost build of Sonic Crackers in one of them! Think it was from Yu Yu Hakusho: Sunset Fighters. Again no connection since that was from Treasure while Sonic Crackers was from Sega themselves.
Weirdest one was Sonic's Edusoft where it has sprites from Winter Olympics. Same developer but there was a big age gap (Winter Olympics started/finished in 1993 while Sonic's Edusoft was from 1991). Turned out it was the cartridge that they used and was rewritten later on.