Loved how the theme had two dimensions - the surface level theme and the surprise rebus! For some reason the puzzle wouldn't take TWO in the rebus square but the number 2 worked.
Interesting - I was just able to solve in a private session with all TWOs . Do you think it's possible there was something else you changed when you switched them to 2s? I'll take a look at the code and see if I can figure out what else might be going on too