If nothing else, I really enjoyed how smoothly this game runs in Ruffle. The controls are responsive and everything works without an inkling of slowdown.
The biggest gimmick of this game - that being the different ship types - is honestly not that interesting. Most of the variants are objectively bad, such as the random teleporter, the bullet going toward the center, or short-range rapid fire. On the other hand, I found the rockets and long range "sniper" ships to be significantly overpowered. These are things that should probably have some kind of tradeoff to make them all competitively viable against each other, or perhaps to have some kind of rock-paper-scissors where certain types have an advantage over others.
The map itself is very odd. The gravity well in the center is a neat idea, but it's way too strong and also doesn't matter for the AI players at all. What if your bullets didn't damage ships, but instead stunned or pushed them? Pushing an enemy into the gravity well would feel really satisfying. Having multiple arenas would be nice, too. What if the map was larger and had two gravity wells?
A couple other balance things are in order, I think. First, the ships need to loop around from one side of the map to the other faster. Too much of the combat happens completely off-screen, partly because you have to go far off screen to respawn on the other end, and partly because you can't spend as much time as you'd want near the center because of the aforementioned gravity well. Speaking of map balance, there seriously needs to be some invulnerability to prevent spawn killing.
The basic engine for this game feels great but this needs some pretty serious rebalancing.