(This may have minor spoilers.) It has a great aesthetic and mood. It has an interesting story, though I still don't really understand what happened. I understand they wanted it to be ambiguous, but I wish they provided just a little more detail. The ending is even more confusing--Does the ending animation just go on forever? I spent a few minutes watching it and pressing buttons, trying to make something happen, but nothing changed. It makes the game feel kind of incomplete, and I didn't get the medal for it, although I see that some others did. It's unclear if the game is actually over or if I'm missing something, but I'm assuming the latter.
Also, I wasn't expecting the later areas in the game to be so frustrating. There's a long, very difficult area with no checkpoints that requires precise timing and reflexes. I slapped my laptop's keyboard in anger more times than I'm willing to admit. I honestly wasn't certain I was going to complete the game, but it was intriguing enough that I kept trying. It also seemed like the birds were able to kill me before even actually touching me (especially the first one). Other enemies might have had this problem, but it was at least more noticeable with the birds.
All in all, it's a good game. I might try out some of the developer's other games later.