I love this game! Great movement options and fascinating mechanics. xPhere’s description is spot-on: the upgrades are in your head, as you learn more and more.
A few minor issues:
- I couldn’t make it full-screen on Windows. That would be really good, so I can stop accidentally clicking on the window frame instead.
- Collision detection near walls is a bit dodgy, with my shots (or enemy shots) disappearing, and with spikes atop a wall hurting me when I’m on the side of the same wall.
- An autofire option would be fantastic. I get that fast-clicking is probably intended to be part of the challenge, but I found it really hard to do—and I don’t have any particular problems or disabilities. Someone with joint pain, say, would be unable to enjoy this fantastic game. That’s why I suggest making autofire an option, preserving the challenge for those who want it but making it accessible to others, too.