I unfortunately didn't have the time to finish the whole game with how busy I am, but I did get through about two of the collectibles. This game reminded me of the super old Adventure game on the Atari. I thought it was really cool in that aspect, and I thought that the game fit the theme really well!
What I can say is that the collision boxes of the enemies seem small, either that or they are just really small for the limited aiming control the player has. Trying to run away from them but also stopping to turn around and shoot makes it really hard when they are so small. It also made it difficult to keep going when I died because it resets the whole level, but that's probably part of the challenge and I'm just impatient :)
However, I loved the game idea as a whole. I also really loved the shooting particles and their glow, I thought that was a really nice touch!