I really appreciate the feedback. Do you think there would be a need for multiple difficulties? We have in mind some variations which could make the game easier or harder.
Difficult to say. The ultimate goal is to put half the deck in the black pile, half in the red pile. Tweak too much one way or its opposite, and you wind up unwinnable (because more than half the deck is red or black). It's at the very least a unique mechanic for a solitaire.
