I liked the idea.
Holding only one key is cool. Maybe I would have included portals, bridges or some other way to connect two dead ends or including switches, but I know that ther's lots of time limitations, so it's a really good game for having such as small time. Specially making a puzzle game, that requires such great skills.
Congratulations!
Here's mine if you can spare some time playing it. Many Thanks:
https://itch.io/jam/gmtk-2019/rate/463337