Arguably the biggest addition t' Portal 2 be the new two-player co-op campaign. But, did ye know that Valve be also working on competitive multiplayer as well? Valve's Erik Wolpaw told 1UP that they "had something up 'n running -- the best way t' describe it be sort a speedball meets Portal. ye know, a sports analog." Essentially, the goal be t' pillage a ball from one end t' another, using portals.

But don't expect t' find this mode in the game when it ships next year. Why? "It quickly became apparent that while it be fun for about two seconds t' drop portals under people 'n things like that, it quickly just devolves into pure chaos," Wolpaw explained. "It lost a lot a the stuff that be really entertaining about Portal."

While Valve have given up on competitive Portal-ing, that hasn't stopped the fan community from creating their own games. Team Portress, for example, mixes a Portal Gun into Team Fortress 2, with some hilarious results.