This is a good game, the UI is really clean and I love this sort of plan-for-encounter mechanic. Gives me lite Persona/calendar-RPG vibes where you need to strategize your prep for what's coming, and that's just a dopamine factory for me
For feedback, it feels a bit weird losing your stuff every round, but I get that's to balance the gems out. I'd also say that certain upgrades feel not worth it, because flooding the arena just does more damage unless they have a certain perk. I don't know how to describe it, but they feel too reactive rather than proactive (or maybe the other way around)? Like if I lose the flood every round, the only reason I'm not using it is the gem cost, and there's no reason to pick it over another 20 gem thing. I think it'd be really cool if there were waves of enemies where flooding one person could buff another person for example, so it's more of a puzzle on what to pick?