I actually really liked this one! Here's some feedback, hopefully you can find it helpful!
- The most fun i had was when I hurled a spear across screen and hit someone, but since enemies generally came in rows of 3, i usually just found myself running underneath the row, and shooting straight up. To encourage players to play the "more fun way" I'd recommend splitting enemy spawns across the screen instead of having them in rows, and having more enemies that each take less hits to kill. This would encourage players to run around more, and hurl spears constantly, which is fun!
- I think the first wave was really long, I was super surprised when the first upgrade menu showed up! I'd personally shorten the length of the waves especially the first one, more upgrades is more fun, and the faster it starts getting challenging the better!
- For game feel I'd recommend screenshake for when enemies die, and for them to leave splatters of blood on the ground where they died. I liked the on hit blood splatters, just a bit more effects and this could be incredibly satisfying.
- I REALLY liked the fact you had a volume slider on the front page, I have to start implementing those.