This game might have had a simple concept, but I still found it really fun. The core loop of picking up boxes and sorting them is interesting, and the sound effects really add to the experience. As others have said, some up front instructions probably would have helped make things easier to figure out. Additionally, my first thought as a tester was "I wonder if I can fall off the map", and it was surprisingly easy to do. I think adding a barrier to prevent players from doing this would be a simple but important change.