I had a version with larger blocks and a smaller map, but it seemed too easy to play, so I experimented a bit with different sizes, and the current one is something that looked optimal to me. I might revisit the smaller map idea if/when I implement a better maze-generating algorithm.
Regarding the controls, this WAS a limitation because of the library used, but in another comment I received an idea how to work around it, so it shouldn't be the problem anymore. As we are in the voting phase, currently I cannot upload the new version, but if you would like to try it, you can do it on this link.