A little on the simple side, IMO
This game follows the same format as The Lost Vikings. You must solve puzzle by jumping on and pushing boxes on top of switches that can raise or lower platforms or drop deadly spikes. Don't worry; there's no fall damage, so go ahead and jump that cliff if it'll save you time. This ain't Lemmings.
I would've personally preferred another level or two of complexity. Ya know, give the characters different skills, add a few different elements to puzzles, etc. Off the top of my head, I can imagine conveyor belts that make it impossible to cross in one direction, or perhaps icy floors that you cannot stop on. Cooler still if you can interact even more with the environment.
All that said, though, it's a pretty well-made game.
Music's good, too. I like the music.