Okay, I really want to preorder Portal 2. I am just worried about buying it and then it wont run well on my mid2009 mbp. Its the 2.26ghz 13" of the 2009 line (http://support.apple.com/kb/SP541) I run portal, team fortress 2, CS:S, and garry's mod on medium-high settings and it runs well. Any suggestions would be great (or if you somehow know for reals) on how it will do before I go ahead and buy. Kinda wish there was like a demo or something.