I have been thinking about slightly altering the parry mechanic in my little game here. Currently, parrying a blue bullet adds to your charge meter. When the meter is full a shot is automatically fired to damage the boss. I am thinking of changing this so every parry shoots at the boss, dealing more frequent damage but less per shot.
Oh lol. Press c next to a blue bullet (Only today did I add this to the second boss)
For the first boss, if you are having trouble finding blue bullets, wait for the homing rockets to be released. Wonder if you could make those rockets hit an unintended target?