Artwork is beautiful! Cute MC always makes me happy, and the slimes are also way too cute. It's a shame you'll need to commit slimiscide, but otherwise nice little game! The controls are great, pacing is also quite nice, though it gets much easier midway through. The upgrade system is quite nice with a ping option, which is really funny. I also like the "Trap" very much as it adds a bit of depth to otherwise brainless endless twin shooters. I end up using that quite a lot and had a lot of fun doing so. The effect also looks great!
For some criticism, I'd say the game is still a bit on the easy side once you pass around 50 waves, and the upgrades are way too cheap later on as such I've just got too much to spend. The game would also benefit from a few more enemy types. Adding some variety would make the game stand out more. Ah, the game also lags after a while (130 wave +) but I guess that's just a stretch as that point.
Anyway, love your game. Would really like to see more about the MC in the future! Great work!