Portal 2 day one, loved the first and I can't wait to play coop with my buddy in Portal 2. MK I like the looks of but would probably only play at a friend's house. And being a multi console owner who isn't a massive fan of pointer controls Conduit 2 just does nothing for me.
sales-wise it'll probably go:
MK > Portal 2 > Conduit 2
may be underestimating Portal 2 though.
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