This is great! Feels like a really complete game, and I love the art style and music. Easy rules to pick up, but still hard enough to master that you can't help but make mistakes - then keep playing repeatedly to try avoid the mistakes you made in your last run.
One of my favourites in the jam so far for really keeping it simple and focusing on that one tiny idea, keeping it simple and polishing it super well. Nicely done!
I think you could probably increase the time pressure a bit, so there's less time to think clearly about what weapon will work (I think you might do this already as the game progresses?) Alternatively, some kind of bonus for attacking quickly, e.g. a meter that fills up towards restoring/adding a heart, Both of these could incentivise acting as soon as possible to add more tension.