First of all, I'd like to congratulate you for having the confidence to put your work up for public commentary. (The fact that I chose to lead with that should be a hint to buckle up for a scathing review.)
This game would not even be a decent in-house alpha. Making the arrow keys act as acceleration is counter-intuitive, the max speed if any is altogether too high, and it is entirely possible to go offscreen. It also appears that to reverse direction, I first need to decelerate.
Two things I expect from a game labeled as "bullet hell" are that the main character has a one-pixel hitbox (and the bullets have a large hitbox), and that the bullet patterns are visually interesting, both of which this game lacked.
The graphics were quite adequate, except for two details. Those blue bubbles aren't even circular, and the square bullets are off-putting. The single sound effect you used is somewhat irritating.