Really loved the concept. I feel it might have been too ambitious for a 48h jam, but I'm impressed by how much you got done in the time. The art and UI were really clean. As others have said, it worked fine once I was using the arrow keys instead of WASD.
One other small thing I'd mention (also about the keymap) is that Esc shutting down the game was a bit frustrating as my brain has that keyed-in as a menu/options screen. There was a couple of times when I instinctively pressed it and had to start from the beginning.
Otherwise a really good job, nice work!