First off I want to say I love the level of polish on the ui, the clean graphics are satisfying and look great.
I'll keep playing this to figure it out. I imagine the upgrade tree is what is meant to make this game playable. It seems to take a lot of inspiration from brotato / survivorlikes, but it has some regressions in my opinion.
Paying money for heals? Hate it. I'd prefer to start with very little hp, and then have risk increase if I don't prioritize hp upgrades, rather than having to pay my upgrade money for bandaids every round.
No free upgrade choices starting out. You can spend multiple waves without making a single upgrade decision, which is really the core of survivor likes fun. In brotato and vampire survivors you get upgrades on level up, which happens quickly.
I don't understand the weapon letter system at all, why they must "contain a letter" and I find it annoying when half my options are for a letter I don't have. (even less choice)
The starter weapon is super annoying to use. The spread is so high, and it's unnecessarily underpowered.
Overall I think the game ramps up too quick, shows too much complexity all at once. It's okay for games to be easy, at least at first. it's fun to win. I'm gonna keep playing and figure out what this game is about, but the new player experience is pretty rough at the moment. I'd recommend giving the user upgrades from the end of wave one and generally make it easier starting out. The first couple waves can be pushovers, and in general the game could be way easier starting out, and ascensions for improvement.