A small and nice puzzzle. It's quite obvious to me that we should put nonexpanding tiles first and diagonally expanding tiles last, but still it is fun and challenging. However, I doubt there will be multiple solutions in several levels and I wonder whether it can be solved logically without wild-guessing / brute-forcing.
It would be better if full screen is enabled and the blocks are set to snap the grids. Also, the resulting board can be a non-rectangle to increase the variety.