Very cool game, although I think there are two main criticisms I have.

The main one is that there is simply too much waiting. The last level took me 7 minutes in total, and a very large chunk of that was just waiting 6 seconds repeatedly for failed throws. Most of the time, there was not even any threat -- I was clearly outside of the blast radius. I don't see any real reason to make me wait so long between attempts for the puzzles. I think there should be a button to simply reset the current room, to avoid so much redundant waiting.

This ties into my second point, which is I don't think it is a good idea to make me restart the whole level when I die. Now, this one could be argued to some extent -- there is something more novel or crunchy about a puzzle game that punishes you like this. But to me it mostly felt more annoying than anything. Each section is already so difficult (and, with so much waiting...) that I figure I would have been much more likely to quit the game had I needed to redo any of them.

There is something quite fun about a puzzle game with such a high focus on execution. It reminds me of the kinds of platforming games that I like, where each level is sort of like a puzzle of how to actually traverse it, plus the question of execution of the solution. I think the puzzles themselves were also quite nice. To be fair, most of them did take me very little time to figure out the correct solution for (and then much longer to actually execute that solution), but I think there was a lot of good use of the mechanics. As an example, for the second enemy puzzle, originally I was trying to do something like bounce a bomb up to hit it, before I realized I could just chuck the bomb with a very short fuse. That's a nice interaction of mechanics.

One small detail I really liked was the way the various tutorial text would end up applying to multiple rooms, e.g. where you would go up and then come back down and read the same text in the next room. Maybe not intentional, but it was fun.

At least my initial thought when playing is that I would have appreciated a per-grenade timer. For me, counting manually usually resulted in the grenades exploding at a time I did not expect. But, once I started synchronizing with the timer, I managed to get a bit better (still not perfect). There is definitely some fun factor in having to do this kind of counting, and it is pretty cool from a design perspective. So, not sure exactly my conclusion about this aspect of it, but it is something I thought about while playing.

The graphics are nice and clean, and the grenade throwing action feels pretty good, although I definitely did not master it. Personally I thought the music was fine for the 20 minutes it took me to win.I did get a little bit jumpscared by the grenade effect sometimes, especially the first time I died to it, it might be a little loud but it might just be the screen shake (I usually disable screen shake in games).

Overall, I think this is a pretty solid entry, the puzzles are cool even if the waiting is a bit frustrating, and I think it is overall well executed. Nice job, especially for a first jam!