Very clever core mechanic!!
I think having O and P feels kinda awkward to use so I would recommend trying either offering left and right mouse clicks or using the arrow keys with Z and C, a trend I've seen with PC games like this that don't have mouse controls.
I think the bullet speed during the initial firing and the recall should be much faster and I think some interesting powerups and enemy types could help break up monotony too. I found myself finding it awkward to hold down P to recall the bullet with the homing and kept thinking it would feel a lot better if recalling was way faster and just direct to the ship, so you could dash behind some baddies, fire the bullet, dash around some others, quickly recall it through them, and so on.
Very cool concept, keep up the good work!