Very enjoyable and polished puzzle game!
I've had some trouble understanding the mechanics at first, but after reading all 5 pages of instructions, it became clear :)
When it comes to UI, I had trouble finding the "enter"/"accept" button at first, and after a few tries I realized it's the "C" key. Other keys were marked very clearly.
When trying to play with a mouse, one thing I missed was dragging the selected tiles :)
I had fun while twisting my brain on this one. Good job!