I just beat it in under 10 hours.
Here's my breakdown.
It was -awesome-.
Wheatley as the final villain instead of the lovable ball of cybernetics? Brilliant. Never would've suspected him. I was half expecting it to be an insane AI Cave Johnson.
Game was a little too long at the end and the previous Aperture Science incarnations were a little dragging... Meh but a minor tarnish on an otherwise stellar game.
Seeing the Borealis' life saver in the game rocked balls(I think despite my misgivings with the Half Life series, I think I've finally warmed up to it).
Lesse.....
New portal mechanics were absolutely balls out fun. None of the chambers from the demos showed up in the retail game, which made me kind of sad. Neither were the refreshing in real time chambers. Oh well. Just expectations set up from pre-release information.
I hope that map makers really get on the ball with this one. Light bridges, excursion funnels, the three gels, arial faith plates... All awesome.
When I wake up or decide to tackle my last Monster, I'm going to tackle Coop. I hope it doesn't suck.