issac newton presents asteroids
a neat little concept, and i had fun trying to balance small course correcting shots with big blasts to clear the screen

sometimes the enemy circle would disappear but the aiming vector line would remain, though i dont think i could take damage from it

with a little tuning this could very well be a classic arcade game, very nice!

Great controls, like how momentum is imparted by shots. Also hold for shot charge was good. And losing diameter (instead of overt lives) was great! Aspect ratio was incorrect for my screen, so I had an egg flying through lemons...

What a lot of neat gameplay emerges from a few relatively simple mechanics.

Forget Mega Man Soccer—this is Mega Man Ice Hockey.

Cool ! The movement and mechanics are nice. It's fun to play. 
I think this could work "Asteroids style" too, where anytime the ship goes off screen, it re-appears from the other side, like an infinite canvas.  If you haven't rated it yet, try "Momentum Command" it's pretty similar to your yours. 
I'm very sorry to have to say this, but....
I wish "k was shot."   :) 
This totally subjective, but using my other hand to fire feels more natural. Or just provide multiple key bindings and let people choose. 
Great job.   

The core gameplay is quite fun. Building up energy in a strategic way was nice.

This is actually kinda addictive! Much more fun than asteroids, and really juicy sound effects.

Intense jellyfish energy