I like the artwork, and It was a nice surprise to see the animated wall in level two! It made the game "bigger" and it made me to think "whats the story behind it?" and I think its no small feat to make the player "wonder"
I had fun with your game, but I would work on some things:
-The aesthetic was the right one, but I wouldnt choose pink to stand out. I would rather keep the color palette simple, the grey black and beige are great to work with.
-I won the game! but I had the same "game over" that you get when you die. I feel that you should check that out, the end of the game should (and its a matter of opinion) "wrap up" the experience and I belive that you can exploit it better.
-Be careful with the hit boxes, it was hard to avoid the bullets but it also provide the player a chance to exploit the enemies and hit them from above or below.
-I had nothing to stop me to beat the level. It has enemies and obstacles but I could avoid them and win the level without a fight. I belive its important to give objectives to the player and "kill all the enemies to win the level" its a simple way to give something to accomplish in order to keep the player engaged.
I like the sprites and I feel you had a story to tell here, and it would be awesome If you keep working on that. Thanks for making it! it was fun to play! :D