This is a beautiful game with an incredible presentation, but with gameplay that's a little rough around the edges, which is enough to stick out with how immaculate the rest of the game is.
The boost being with WSAD is fine for static jumps but there are a few running jumps where it competes with movement and feels really awkward. Level 3 is a big difficulty spike with the amount of precision jumps needed to get around, a level of which is never demanded of the player again. Getting an item off of a ledge needs some pretty finicky timing, and I'm pretty sure I managed to exploit a level (I think it was 7, the one where you have two weights and a torch and need to loop around a room to open a switch in the center) by throwing an item diagonally down into a corner you need to boost to get over, and picking it up in the tiny frame window where it's grabbable before it slides far enough off the ledge.
That said, like I said before, this is still a very good game! To comment on the art feels like reverse-nitpicking, there are a lot of really small things about the aesthetics that add up to make something that's truly, genuinely great. The sound design is minimal but what's there feels intentional and adds so much to the atmosphere. And the endings of the last two levels were genuinely really cool and unexpected moments. This has also been one of the strongest implementations of the limitation I've seen so far, great job!