The very same bug was experienced by some of the playtesters of this game, where the movement controls don't work. I was unable to discover the fix for the bug, as the controls would work fine when played by other playtesters on different computers (but the same operating system). The two possible solutions I can think of right now is try running the game on a different computer or, if you have the godot engine, you could directly download the source code from Github (I believe it should work), import it into the editor, and press f5. Hopefully that helps!