Thanks for playing!
I agree that the enemy projectiles are too fast. Slowing them down was on my to-do list but after crunching to finish level 3 and the boss fight I didn't have the energy for any extra tuning and left it be.
Enemy projectiles going through walls is intentional, as them being blocked by blocks would have made the game significantly easier and the game is already quite easy (if you know how to exploit it(swapping worlds to dodge projectiles is key)), but I did go back and forth of this choice a few times and am still considering what way I want to go on this mechanic in the definitive edition after the jam. Enemies are going to be completely overhauled one way or another.
Velocity, however, is punishing on purpose. After all, you'll never take fall damage as long as you hold that last bullet to cut your speed! I wanted it punishing specifically to encourage the player to track their ammo count. I set the fall speed to limit at a specific threshold (you just kept falling faster and faster in the first few days of development lol) and tested the threshold a lot to make sure that you had a window to identify that the floor was coming up so you could cut speed. I may tweak it more in the definitive edition, but I'm very married to the idea of it being punishing. Maybe instead I change it to have multiple damage thresholds based on how long you were at terminal velocity instead of just 2 hp flat?
I appreciate the feedback!