Puzzle Moppet is a grid-based platform puzzler which takes Sokoban-style gameplay into the third dimension. Features include manual undo, automatic undo upon death, and level performance evaluation based on blocks pushed and elevator rides taken. The plot barely extends beyond the game title, so it's all about your spatial puzzle-solving ability here.
The game's interface is rather unusual. Freeform camera movement and view-based WSAD character controls are combined with the constrictions of a three-dimensional grid. Thus a slight mouse movement can cause the character to turn at a 90-degree angle, which is rather inconvenient if, say, it causes Moppet-chan to plummet into the surrounding abyss rather than complete the level with perfect execution. Thankfully, this default feature can be disabled if desired, although expect a lot of snapping-to-grid whenever you take an action. I also experienced random game freezing/display issues, the frustration of which need not be elucidated.
Even with these issues, the puzzles are perfectly well-designed, and it's a pity the game didn't get the commercial interest warranted by these brainbenders. But as a result of the poor reception, the developers released the game for free! Who can complain?