I enjoyed my time of a few rounds, even if I didn't win one. The gunplay felt good, and the gun and player modifiers were fun to mess around with. UI is pretty decent. Only Issue with it is that the scroll wheel sometimes scrolls twice instead of once sometimes for weapon switch, dunno if it's just my end though. It's a bit hard to understand the difference between the red/blue/purple encounters, though I'd assume I'd figure it out if I played more. Otherwise I think the map icons were easy enough to figure out after encountering them once.
The levels did feel a bit long to clear, especially the open ones. I ended up marry-go-riding around the level to kill the orange towers and orbs. Though it was entertaining still to do the dodging and fighting, I was just getting a bit weary to do it for that long at once. Though I don't think there's much to be done, it seems to be the style of shooter this game is about, with lots of enemies to take on at once.
Enemies felt pretty good, each one has a purpose and doesn't feel tacked on. Only thing that felt weird are the big purple guy's attack. I can't tell if it's an AOE that sometimes triggers or if you get damaged immediately upon entering the circle. Would probably be fixed with an attack animation of some kind.