There is not enough reason to shoot. The first time, like others, I spammed a bunch of projectiles and killed myself. The second time, I just shot 2 times and slowly moved up and down, the enemies did not have time to reach and died
With this mechanic, you can definitely come up with a lot of things and make an interesting game, but first you need to motivate the player to shoot so that he gets some additional reward for it
P.S. The game is not bad, I'm just trying to push you so you can make it more interesting