Fun game. Like it. Want to point on some things that raises some questions on your game design choices.
1. Everything were fun until seeing "+830% gold multiplier". It is broken. You literally can buy almost anything in 2-3 runs after that.
2. The "magical numbers" stat increases. Why buying "arrow rate" decreases it on 0.093s? Why not 0.1 or at least 0.095. The 0.1 option sounds better though. Same goes for almost every other stat upgrade in this game. Just round them to the nearest number after 0 and everything will start looking better for sure. Your design may work but only if you implement stats calculator or something in that sort so I don't have to calculate those 0.0XYZ number in my head manually
3. Following stats problems, would've been pleased to see some stats menu where I can see them(i.e. firerate, damage, damage-area etc.). Otherwise, maximum what I can do is to look at the base stats of my bow and sum everything up. Not fun.
4. The upgrade "Time chance per kill" isn't necessarily broken, but you can stuck in your fight scene with slimes for like an eternity. When buying all 12 upgrades, it gives you overall chance of 45% to get +0.2 seconds after a kill. It is A LOT. Because at this point of the game your screen will be full of slimes and your attack range will be long enough to kill at least 5-10 slimes each 1-2 seconds. Just adding option to leave the fight would've been the bare minimum to fix that problem
5. The "damage increase" upgrade not working? At least it didn't seem like it works. Literally not getting the increased damage