Very interesting game!
I liked solving the puzzles, tho I gotta admit I skipped the tutorial parts, read them very fast, and was just eager to start the game, so I just went into first level, entered letters and checked the output, and tried to work my way back from the output, it was fun, at times I understood the level logic, at some times I just brute force some results, and I even went as far as checking GitHub repo source for some answers! :D Did not finish, as dont have that much time now.
Overall good, only thing maybe holding backspace could delete letters, or there's a reset button, or any faster way to clear input. Or its just that I'm used to not tap backspace that much.