The idea is very interesting, there is a surprising variety of opponents and the overall execution is good. Plus the name is clever :D
The way things wrap around when they leave the circle is a bit difficult to predict, even after recognizing the pattern. Combined with bullets always coming straight back at the player (and forcing them to dodge) the game is very punishing about missing. Maybe the key is holding a sufficient number of opponents in the circle to eat stray bullets?
It might be interesting to see what the game looks like with other shapes, especially if they make wrapping easier to predict. Maybe a square?
I didn't notice any of the lag the others mentioned, so maybe that depends on environment it's run in.
The game crashed a few times, but only after loosing so it's not a big deal. Here is a stack trace.