This game has a really cool concept!
A couple things that would have made it a bit better -
Instead of each level being randomly generated, having a couple pre-set tutorial levels to introduce players to each type of reflection.
Also, a way to flag locations on the board that you're keeping an eye on, before you're ready to place your actual guesses. Similar to how in minesweeper, you can place down flags to remind yourself of where you know the bombs are, or how in sudoku games there's usually an option to note two possible numbers in the corner of a blank space.