I dunno, I thought it was more fun when it was being [spoiler]"Portal, now with Stephen Merchant!"[/spoiler] than when it was trying to be [spoiler]"Bioshock, now with J. K. Simmons!"[/spoiler]. And when it wasn't suddenly crashing to desktop. Which was every 30-45 minutes, fourteen fucking times in a game that was 7 hours including reloading and retreading from crashes, including one crash in the middle of the fucking ending song.
It was nice to have like ten different new puzzle mechanics but then solutions became less about "how do I get from here to there" and more about "Okay, they're giving me a repulsion beam, repulsion gel, and a sloped surface, how will these combine". Felt like an adventure game, combine X with Y until the game accepts it. The relative scarcity of portal surfaces exacerbated that - places to put portals were mostly just the places where you will need to put portals, so instead of figuring out where to put them you're looking around for the place it wants you to put them.