Thanks, I thought that was a fun idea to encourage precision and discourage spamming!
For the shooting, it's based on Galaga- so only 2 projectiles are able to be on screen at once, but it resets once it gets destroyed, which is either when an enemy dies or when the projectile reaches the end of the screen. If you can keep hitting the enemies and not miss, then you can hold the space bar to constantly shoot! I liked that about Galaga, so I based it around that. Hopefully that extra info helps!