There are duplicates of Mega Man 2 and Mega Man 3 for the NES. The problem is that the mis-spelled ones, Megaman 2 and Megaman3, have the complete sales data. The properly spelled Mega Man 3 has some sales data and the properly spelled Mega Man 2 has none.

Mega Man X, Mega Man X2 and Mega Man X3 for the SNES have mis-spelled entries. They are improperly spelled Megaman X, Megaman X2, and Megaman X3.

Super Ghouls 'N Ghosts for the SNES has two entries, both spelled improperly. Super Ghouls and Ghosts, then Super Ghouls & Ghost. "Super Ghouls and Ghosts" has the more complete sales data, so I guess that's the keeper.

I say as long the words are spelled properly, things like "and", "&", and "N" aren't such a big deal at the moment.

GEN

Street Fighter II Championship Edition - http://vgchartz.com/games/game.php?id=6946
Street Fighter II Plus - http://vgchartz.com/games/game.php?id=6452

(the real names are Street Fighter II′: Special Champion Edition or Street Fighter II ′ Plus in Japan)

Xbox360

Tomb Raider Anniversary - http://vgchartz.com/games/game.php?id=12366
Tomb Raider: Anniversary - http://vgchartz.com/games/game.php?id=12895

Updated

endless ocean\forever blue

ioi im going to put "ioi" next to the ones that need merging.

guys keep this updated so we can fix things

ok some other mod's turn to work on this.

Mario Golf for 64 has two entries.

Mario Tennis for GC also has two.