I actually got round to seeing this last night.
And I thought it was BRILLIANT!
The detail they put into it was great, and the use of other games-like Pac-Man, Q-bert, Street Fighter, Sonic, etc was inspired. You cant help but play the 'spot-the-character' game whilst watching it (In the Game Station scene I even spotted Paper Boy in there!
It's the little things I like, like the way all the characters in the towers block (and that barman) all move in quick jerky movements, like they do in the old 2D arcade games.
There are only two (very minor) things that I just want to point out though-firstly, I felt that there was a bit too much time spent in the Sugar Rush game.
We see four worlds in this movie (Ralph's game, Hero's Duty, Sugar Rush, and the Arcade itself), five if you include the Game Station.
And yet we spend a lot of time in Sugar Rush, which is okay but I would have liked to have seen some more of the other worlds/games has well.
Also, another thing is the use of product placement (Nesquick, Oreos, Diet Coke, etc). I've nothing against this, but the lack of subltlty about the how they did it (and the fact that it was SO OBVIOUS to see it) kind of bugged me a little bit. :P
But these are just minor quibbles, and I really enjoyed it.
I might even go and see it again sometime (possibly).....