I think movement and shooting is quite nice, and overall with some tweaks I can see this becoming a fun game.
As for the enemy pathfinding, perhaps context-aware steering would help - basically, that’s an easier way to have enemies avoid obstacles and keep distance from each other. Although if you want complex level layouts, you’ll need actual pathfinding. When I was fiddling with it, it was not easy.
As for the art, perhaps picking a decent palette on Lospec could work? I think colors go a long way.
Regarding gameplay, I think enemy hitboxes for projectiles could be bigger as that IMO would make the game a bit more fair.
Overall, nice job!