Cool, I like this game! I beat it in half an hour. I think the difficulty level of all the levels is really good, except for the last one, which I found frustratingly hard, though I did eventually solve it. All of the other puzzles felt impossible at first until I played around and had the satisfying "aha!" moment, which was nice. I could imagine making them a tad easier, but I don't have a strong sense of whether that would be better or not. I do like that the game taught me its mechanics in puzzles instead of in text.
Speaking of text, I found the screen explaining the controls a bit cluttered and hard to read. I think there could be more margin in between each pairing of a keyboard icon with the text explaining what it does, so that it's visually clear what's grouped with what. But I also thought that presenting all the controls on one screen right at the start of the game just felt a little overwhelming — I remember thinking "Push/pull? What does that even mean?" It might work better to introduce each set of controls only as it's needed. Maybe they could be part of the background of the levels where they kick in. Then the player would have the chance to learn them one at a time.
I think the physics engine is just a little bit funky-feeling, but fine for the genre of game. There weren't any moments where I felt like I got away with something because of a glitch in the physics engine. I did feel, in the last level, that I was surprised that I couldn't drag my corpses out of the spike pit to get them onto the red button. That felt a little unfair, and I wondered if maybe it was the physics of the game just being finicky and I was supposed to be able to do it. I wonder if there's a way to communicate that that's not the intended solution to that puzzle. Maybe the spike pit could be deeper.