Really fun game!
The movement and "feel" of the player is exceptional.
The art style was also good and matched with the whole concept.
I liked the action overall, but I am skeptical about the scaling and what it means to the game.
I survived 10~11 minutes when I found out that there wasn't anything else and I just quit.
The game felt great at about 3 to 4 minutes in, where there was balance between the player power and the enemies. That was the time when the game was most challenging and most fun. After the 5 minute mark the player becomes overpowered and I just stood at the center of the screen spraying bullets left and right destroying any enemy on sight.
A few things that come to mind that would make the game more challenging are a type of enemy that shoots bullets, enemies health also scale the more time you play, the gameplay area also scales so that more enemies are threatening the player, with each level the player grows in size (so that it's more difficult to evade enemies).
To conclude with, I really enjoyed the game and believe that it is a great concept that can grow into something more!