It's really well done despite being so simplistic, making it effectively a minimalistic game. The controls and mechanics are slightly confusing, because it takes a bit to find out how to maintain a larger playing field, as opposed to being stuck with a smaller one. Perhaps some "tips" in-game" would be helpful. Other game modes for a second or updated version. A game mode where as your dodging, there's little enemies homing in. After a while perhaps they speed up. After so many dodges, let's say 25, you can get a temporary bonus to shoot balls and enemies in the same sense as an old fashion game, where you have one projectile, and you can't shoot again until it's collided with something. A game mode where you have one always opposing your location, whilst another one always opposes your position OUTSIDE the circle, on an even bigger circle. Only counting dodges of course in/on the circle you happen to be at. Perhaps an automatc switching every so often, either by random intervals of time, or by points basis.
There's so much you could do with this game! I humbly ask you to stick to it, and create something even more suprisingly unique than what you've shared with us here. :)