Well... I guess I can answer my self now since I picked it up while on sale a few days ago.
The game is indeed unplayable on an laptop without an integrated card. I get 15-20 fps there and it's just awful to play an action focused FPS (well any game I would say) at such low framerate. But to be fare, it's an unreal engine 3 and I haven't seen yet a UE3 game that works fine on an intel HD.
Now, with a 650m I would say it's plays surprisingly well. I'm playing it on medium details at 720p and I get for the most part 60 fps, and to be fare, the game looks pretty damn good even at that setting. I can crank it up to 1080p and still get above 30 fps, but to be honest I don't see that much quality difference to make it worth the framerate loss.
I must say, however, that I haven't played all that much yet. Only the first few levels so maybe in later levels the performance goes the hell.
As for the game it self, I must say it has been a ton of fun so far. It's just what I wanted, an old school FPS with good graphics, where you don't wast time with week weapons (or no weapon at all) and few enemies, until you slowly make your progress to the better weapons and so. Oh no no no. Remember Duke 3D where you start the game with your pistol and as soon as you jump into the street, enemies start shooting at you? and you can find an RPG almost immediately (if you know where), and later a shotgun all in the first level?
Well this is just like that. You start the game with a simple gun, you walk a few steps and the gunfire starts (and so the great soundtrack), and you can get a second pistol, and rocket launcher, and it's just chaos everywhere!! Also you move fast as hell and you can explore the level all you want trying to find secrets. It's just perfect!!
Very happy with this purchase I must say.
