A neat little demo, the art is nice and I like that there's a co-op feature! Though I wasn't able to properly test it beyond playing both characters myself.
The variety in firing patterns was cool, and I liked the powerups bouncing around the screen. I found the player firing sound a bit grating once it gets beyond a certain point. Also I noticed the sounds seem to be played by the projectiles themselves and not the player. So if a projectile hits something its sound effect is sharply cut off. I would instead just have one audiostreamplayer attached to the player playing the sound effects, so you dont get the crackly cutoff.
I do appreciate the fact you aren't required to repeatedly tap to fire, makes it much easier on the hand.
Good work! Hope you can finish this one post-jam!