This game has a lot of content! I usually play jam entries to the end, and I'll probably come back for this one, I got to level 10, so I have yet to see the final boss.
Binding of Issac/Gungeon players are going to love this one (like me), the game is incredibly fun, the bosses look great, and it doesn't look like at first, but there's a lot of tactic on how to play this. Accumulating hearts in the beginning of the game to ensure you can take a few hits on the harder bosses, leaving coins/hearts on the ground to pick up later when you're at 9, pre-placing bombs to kill bosses faster, etc. Getting damage ups early on really helps as well.
I was honestly surprised when I killed the first big boss and there were more content lying ahead. The sound/music design is great (chill but fitting), controls work really well, and if there's anything I would particularly change is the invulnerability frames. I'd make then a bit longer, so you can breathe a little after getting hit by a volley. That, and having more "unique" items to pickup would be an awesome addition to this game, which is already pretty cool otherwise.
All in all, this is one of my favorite entries so far (I still have a lot to play, but this really caught my attention), great job!