I dig the concept! It took me a while to figure out that you could just hold the keys, and how the stop mechanism isn’t a hard rule, but makes the timer-bar run out faster (which is a clever way of doing that!).
It’d have been nice to know what it a certain game configuration means … what does a lady warrior mean versus a sea-horse or small dragon as a main character, or a few platforms versus a grotto for the ground?
I see you use the letter keys at the corners of the keyboard on a Qwerty keyboard, but already not the case for French/Belgian Azerty of German Qwertz (I’m Dutch so it didn’t bother me), it might be worth using raw key-codes if positioning is important, or give a few alternatives. Or use the arrow keys?