This is a really nice game :) The art style and soundtrack are awesome and fit perfectly together. The difficulty gradually increases by introducing new bullet behaviors and spawn mechanics but the player is always eased into new situations.
The only problem for me was the input layout (the controls themselves work really well and direct) of having movement on WASD but dashing on the mouse. I think for me it would have been easier to have everything controlled by the mouse or the keyboard. Like LMB = fly towards mouse cursor, RMB = dash towards the mouse cursor.
I really enjoyed the game :)