The prototype aspect is well respected and done.
I like the gameplay it is very well thought of. The only problem I had was the left-click spam to shoot. As a player it is not pleasent to smash a mouse button even more with a mouse where precision to shoot is also needed :)
I found myself being like Shweep, preferring to take damage to collect shards than fully avoid projectiles. I did my first run with the really first gun until the end and on the other runs when I changed weapons I died quite immediatly mostly because I couldn't avoid projectiles or because of the number of ennemies the weapon was more innefective than my previous updated one.
For me, some work have to be made on the "rythm" of the game which might be too fast paced or not well balanced but the idea is pretty good and can make a good game if done correctly ! So good job on this one :)