Actually one of the best puzzle games.
The pixel art is fabulous, it feels just right when it changes from small to medium to big and the portal animation is really hypnotizing.
The controls feel perfect, you feel like you are the one moving and it doesn't feel slippery.
The difficulty is on point, only problem I had is Level 17 which was more annoying than hard but that can be looked past compared to all other levels.
The mechanics with the windboxes are really well handled and were unexpected for such a simple concept, it really made it feel more broad.
Easy 5 stars, don't think I'll be changing my opinion on this one game ever.