OMG ... My submission also uses math and equations!
I played your submission and also see that you were very responsive to add undo. Very nice game and of course I love the idea, especially since my idea is similar but different in its own ways.
I found your first 4 puzzles challenging but didn't solve past that yet. Well done.
Please feel free to try out my game and even make a few levels using the built in level editor mode ( Toggle with the <Escape> or <e>dit ). Then you can (s)ave the level and after it is solved at least once, it will appear in the list of available game levels. The list on levels available appears on the main screen when you scroll down.
