This game is pretty cool; the mechanics are great and there’s a satisfying level of juice.
I wonder what your ultimate plans are, because I feel as great as it already is, it is missing things that will make it truly awesome.
For example: the pacing is not ideal; each level starts very hard when all (or most) of the enemies are spawned), and gets easier and even boring as the enemies are defeated. A good pacing should instead go from easy to hard, with spikes and lulls every now and then. Will you work on the spawning logic next?
Next there is the gameplay. It works well, but I feel that most enemies take too long to defeat. In some shooters, enemies die in one shot but they are numerous, in others they take longer to die but there are fewer of them, so there’s a balance, and here I feel the balance is slightly off. This is especially apparent with the tank enemy, which persists and becomes a chore to finish off. Also since the game map is pretty simple, every game boils down to circle strafing. Will you add maps (walls etc), powerups to collect, or other mechanics that zone out the player or encourage them to break their movement? Consider Crimsonland as an example, which has no walls but heavily relies on powerups to keep things interesting.
Finally this game needs some audio love; the visual effects are on point but some sounds are just basic sfxr/bfxr stuff. And music! These would really make things pop.
Anyway don’t want to make it sound like I’m down on this game, it’s great overall. Looking forward to what you do with it next.