Very interesting game
I would give the people hints but they could always just use the walkthrough. The best part of this was how utterly unpredictable it was. I had no idea what was going to come up next and how the game was even working! Thank you for including the hints and of course the walkthrough as previously mentioned. You could put in some more interesting things like more graphics. This is of course a game that does not need graphics as it's a good puzzle game.
It's quite original and that is something I always look for in submissions. Puzzle games are either easy or hard for me and this one was pretty hard. That's the main reason I did not enjoy it as much as I thought. It took some real thought to come up with the different levels. It's kind of like Sudoku, only not as hard (still hard).