A trick (almost cheat) to get around "random size X in under Y minutes":
Just solve the puzzle and don't mind the time. When you're done take a screenshot and press replay. Copy the solution from your screenshot.
The random 6 is still difficult (I haven't done it) but not "impossible".
Oh, about the game: I think it's okay. There's nothing that would give it a very unique feel but it's still good (and pure) at what it is: a puzzle game.
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