Nice way to advertise your engine, I’ll definitely have a look (GBA games? In Rust? I’m sold).
It was quite challenging; I loved how some mechanics just popped up unexplained, and were left to the player to figure out or come back to later (with rooms that demonstrate them if the figuring-out did not work :P).
The movements and animation are very satisfying, snappy and fluid and all, were they all made during the jam?
Also I did beat the boss (yay!) but can’t be sure how I did (got an idea, but not certain about it). I flayed about for a solid 10 minutes before exiting and re-entering the room, and then a few moves later it was over.