Really liked this one! The only negative I can think of was the pick up key not being very intuitive to use.
I loved the concept! As I kept going further and further into smaller rooms, I was thinking to myself why would I ever change from a big sword to a small one? Right after, I walk out of a smaller room into a bigger room and the sword changed size and I was like "Ohhh now I get it!".
PS: Throwing back the projectiles at the enemies felt very nice!