Nice little game! The spinning being used as "invulnerability" is very interesting and a fun concept, introduces a lot of options: do you want to sacrifice your resources in a powerful attack, or do you want to keep them to defend yourself? I also liked the fact that there was a dash, it's a nice movement option to have in these kind of games, but this time it's actually not your main method of dodging!
Tho, I think the bosses could use a bit more fleshing out in their attacks and "impact" overall (also maybe a death animation would be cool). Also I don't know if I did something wrong, but whenever I defeated a boss I couldn't find a way to exit the arena, so I just exited through the options menu.
Also I...think the shopkeeper's wheel broke? Whenever I was spinning it, it kept displaying blank upgrades, and saying "no upgrade selected", even tho it was consuming the tickets. Could it have something to do with the fact that I skipped the shopkeeper's dialogues at the start of my second playthrough? (After I got locked into the boss animation I couldn't figure out how to unlock it because it kept locking up after restarting, so I restarted, but then I found the strategy of dashing towards the boss instead of walking which seems to fix the issue).
Overall, nice game, would need some polish but the fun factor is there!