Really good. Drags for a bit near the end. The writing and voice acting is top notch, Stephen Merchant in particular. One bummer, however is that it's not a hell of a lot different than Portal. It's much longer to be sure, but the gameplay hasn't evolved a hell of a lot. That's not to say that it's not fun, because it is. It's one of the best games I've played this year. I'd compare it thus: Portal 2 is to Portal 1 as Half-Life 2 is to Episode 2.