We find our heroes on the school roof (I guess) when a hole opens in the sky and sucks them in.

Yes, the sky is made of glass in Japan. They find themselves before a castle, and, being clueless schoolchildren, they enter. In order to leave this world they have to pass through the rooms of the castle.

Each room has several creatures and several blocks which can be pushed around the room. Push a block over a creature to kill it and get a key, which opens the exit to the room. You can jump atop the white blocks and then walk to the exit. You may only walk along the blue paths on the blocks you slide around; fortunately these blocks can be rotated. If you push the blocks against the wall in the wrong order, you’re screwed. You can restart the level, but you get very few lives so you’d best get it right the first time. There appear to be four rooms to each world, and a number of worlds unknown to me.

Verdict: It’s not too bad as puzzles go. It’s been done before, but for puzzle fans this one is worth a look.