I found this game somewhat therapeautic to play, with the calm upbeat music, and the satisfying shooting. I do wish that you could shoot with a higher rate of fire, or charge up your shots for bigger, faster bullets. It might also be cool if shooting the bullet caused the spaceship to move backwards a little bit. My team actually made a similar spaceship game for our previous game jam with some of these mechanics I'm talking about, I think your game has more interesting level design, but might be cool to try each others games: https://skallywags.itch.io/gravity-blast
I somewhat agree with what others have said about balancing. It was a really cool idea to make the player prioritize being inside the circles of light, however it seemed a little overbalanced. It made the game more challenging for sure, but its not that fun to be reset to the previous spot simply for staying out of the light too long. Its more fun to be reset because you messed up during a fight with an enemy. So my suggestion would be to give more energy by default, or make the upgrades to energy be worth more energy, and then make the enemy AI a bit faster and smarter, so the difficulty comes more from the fighting and postioning yourself in the light is still important but it won't be the primary driver of difficulty and challenge.
I hope you do keep improving the game because I think its a really cool concept.