From the "stuff I had hoped to finish in time for the GOTY vote but didn't, but then I finished them today so I guess I did, but I already voted" file:
Hotline Miami
I think a lot of people here have written about the great sound/music, the hilarious visual presentation, and the over-the-top gore (including the excellent feedback for using weapons), so I won't say much more about those.
I wanted to mention two things that not enough people are saying:
1) This game controls incredibly well. The introduction teaches you every control you need to use to get through the game. I played with a KBM and I was very surprised at how in control I felt once I learned to use look-ahead and lock-on. Really, really smooth controls.
2) This is a puzzle game, not an action game. By far the bulk of the gameplay involves trying to figure out a good path through the level, rather than actually executing it. You will need twitch reflexes, but it's way more of a puzzle game than it is an action game. Reminded me a little bit of Hitman in that regard. I was very disappointed in a few levels where I ended up up using a gun on the first guy and having basically the whole level come after me, bottlenecking themselves in a door and having me kill them one by one. It's a much better game when you can creep from room to room and keep the carnage going that way.
I do have one criticism. I don't think the game's story or themes are really that interesting. I played through to the second credits, although I didn't get all the puzzle pieces. I didn't find the story that novel, I didn't find the psychological freak-outs all that interesting, I didn't really like the between-level story segments. It came off on the "obtuse" end of the indie spectrum rather than the intellectual for me. I know it's not me, or at least not me more broadly, because I have a pretty analytical mind for this sort of stuff and I generally give games the benefit of the doubt for exploring deeper themes in a hinted or circumspect way.
Still, very very fun and I look forward to going back and working on high scores. Game lasted me I think around 4:30.
QUBE
This is a game that I don't think gets enough credit here. It's short, shorter than Portal even, but it's really fun. A whole bunch of people here complained about the game's final puzzle, and I really can't see why. It's very iterative over the rest of the game, you have infinite time to do it.
The only mechanic that I think didn't work was the section where you played mostly in darkness. Basically I thought that was a very thin veneer for making simple puzzles needlessly complex. Every other mechanic worked well, though. I loved the way that different puzzle types (like the rolling ball + sloped floor) got reused later. I loved the light physics elements.
I would have liked to see more of a story or concept. The ending was nice, but I felt like it would have been nicer if there were anything in the game that led us to that point or, like, any reason I should care. In that respect, the game felt more like a pure arcade puzzle title, with no attempt to have any real characters or story.
I didn't find the game hard, but there were a few sections which required quite a bit of experimentation to figure out how stuff fit together. It was generally good at preparing you by introducing new concepts and ramping them up. Game lasted me a little over 3 hours.