Nice mechanic, the invisible sprites didn't bother me much, what killed me the most is 1. having both character off a platform and falling like a dum-dum, and 2. not being able to press both buttons at the same time when you have the XX pattern with mines. A minor suggestion would be to have the "Try Again" button restart directly, instead of having to click twice :)
Love the art and music, GG on creating those so fast!