Looking at the screenshot GIF with the larger variety of enemies. I think the game would be more fun if you got to that point faster. The 5 minutes it took me to get to wave 6 was a little boring. And when I got to the more interesting enemies. I had taken way too much silly lil' chip damage from the flies. And died to the first real challenge I faced. All the enemies look like a lot of fun to play around. And I really like the compact hectic arena feel. I think the slower nature of projectiles and enemies lends to a more methodical positioning of your character. Which is quite intriguing. Perhaps feels a little more RTS/RTT than fast twitch bullet hell... that might be a weird stretch. Almost making decisions in a sort of slow motion, gives you just that much more time to think your movements through.
I still had fun playing, and analyzing. Keep up the good work.