Simple art style. I like it. It's consistent and really nice to look at.
I think the text at the beginning should have some padding on the edges, so it doesn't go all the way to the edge of the screen. It would make reading much easier.
The dialogue sound effect is a little bit too loud compared to other audio. Sometimes it's a little bit buggy, where the sound keeps going even though the dialogue is finished. Another bug that I found is when the dialogue is near the end, clicking on the screen straight up skips the whole dialogue, instead of skipping the animation itself.
Though the dialogues themselves are funny.
The buttons at the shop is kinda buggy as well. The plus minus symbols inside is blocking the button.
The gameplay itself is pretty straightforward for me, though maybe a little bit difficult. How the bullets bounce around is really cool to see. Though maybe the robots that shoot out bullets can be a little bit varied. Maybe instead of shooting up down left right, it could shoot diagonally so it's more chaotic. The problem with it shooting in cardinal directions is it will just stay at the row/column and not go anywhere else, which is a huge problem if the robot is in the same column as your character.
It's unfortunate how it's a little bit buggy though, with the whole retry thing automatically destroying an enemy, or how sometimes it freezes the whole game.
The BGM really fits with the theme. The SFX are also nice and works with the game.