Fun, easily understood controls and game mechanics.
Nice atmosphere, great music, keeps you In the game.
Why is it called PUMP?
Also dumb levels weren't dumb, just a little more timing oriented than the other levels.
Everything in the game worked and was entertaining!
Not necessary, but you could have included a character name and why he/she was ascending the stairs for a short story behind the action, maybe even an ending scene with the goal in hand.