Level 6 is definitely bugged. There were placed I could move that had barriers, and places I could not move that did not have barriers.
I love this idea! Especially in the later levels where I had to use some brainpower, moving the cube around and finding my route was so satisfying. I'm not sure how scalable this is to a longer-length game, but everything else about it was very professional... graphics, sound, polish (except for the error mentioned above).
I'd love to see this expanded if you can find a way to scale up the difficulty and intricacy of the puzzles. For example, if matching rows of terrain caused them to change in some way, and if you could terraform/activate different parts of the cube to remove different barriers. Add some more puzzle layers to this, and it could be a published game,