This game plays quite well. Very fun!
-Shrink the player's hitbox a little. The hitbox seems to be the entire ship (unless it isn't, in that case, I'm just bad at the game :P)
-Change the "bonus points" item sprite. They look like lighter colored bullets.
-Have an "upgrade meter" that shows how many powerups are needed to upgrade the player's weapon.
-The player sprite appears in front of the HUD, but not the exhaust effect.
-Perhaps if the player is hit, their weapon level is decreased by 1 or 2 levels, instead of immediately reset to the base single shot?
High Score: 106300 (204 kills) :D