At the moment I found two bugs in the game. First one is an OoB, the other screws up the AI of the final boss.

Both are from the latest version: build 2287763 (in case the dev suddenly wants to fix this.)

The out of bounds trick can be performed after defeating the first boss. If you go up to the first red dog there's a bit with two floating blocks to the left and a cliff up top. The cliff doesn't have any collision on the right, allowing you to climb it.

You can't go the whole way up, but you can fly over the level if you glide from there. You do need precise timing because of the birds before the cutscene.

Here's a demonstration video:

The final boss AI glitch is a peculiar one and I haven't been able to consistently nail it. I've seen Ico's run, but his fight seems to abuse stagger.

Anyways, I speculate it has something to do with the way I do the sword combo by using the uppercut and down slash. I've sometimes seen him float quite a distance and seen the chap float both ways. I don't know if using checkpoints influences this behavior, I'm not good enough at this game to find out.

Another video here: