I'm thinkin of buying the game but what are the splitscreen options (gamemodes) for PS3? And are you able to play co-op splitscreen with 3 or 4 players and what does co-op means?

If it is X-Box 360, you have to have him sign in on the welcome screen, just like in Left 4 Dead. What he will have to do is sign in and then you play on the campaign thing.
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