I really dig the art style of this game, it looks really good with the mix of 2d and 3d. The camera shake and sound effects make each hit real meaty, and I like the health bar mechanic that slowly drains so you're forced to go on the offensive. I also like all of the quality of life stuff you put in, such as the arrow markers and the seeing enemies through walls thing.
The gameplay started feeling repetitive until around round 15, which is when the difficulty kicked up with the pink enemies. I would have ramped up the difficulty progression faster, as right now it feels like I'm not really doing anything until the later rounds kick in. Adding weapon upgrades or offering different types of weapons would have also helped make each run more interesting.
I also think that enemies should visually explode on death and leave their remains behind. The weapon hits sound super good, but they also make it seem like the enemies should do more than just disappear after they die. A simple implementation I would've done is take each enemy sprite and cut them up into pieces, then when an enemy dies, their pieces get flown across the floor randomly and disappear after a few seconds.
Overall, great entry! I had a lot of fun playing this. My highest score was round 26.