I think the game runs ok. It's a tough platformer. Graphics are nice and controls are simple.
The timing gets extremely crucial since the character has a small cooldown when he lands, which makes him unable to jump for the next nanosecond, by then which you will have been shot in the face with a fireball or fallen on a spike.
I'm not sure if anyone else has this issue, but the game has this strange millisecond pause throughout, which messes up my timing.