Splitscreen is a reason for me to buy a game, if it gets bad reviews. Every week a friend of mine comes over so can play on the 360. We played almost every co-op game there is, even the bad ones. For example I bought Kane & Lynch 1 and 2 with a friend so we could play a game together, and we had fun with it even though it's not GoW2 or Borderlands.
So my advice for game developers: put co-op in the game and your game will get more sales :)







