Challenge FreeCell changes one thing about FreeCell and changes the whole game with it. The rules are identical — eight columns, four cells, alternating-colour building, any card in a space — but after the deal, every ace and every two is sunk to the bottom of the column it landed in. Nothing else moves.
That single rearrangement inverts the opening. Ordinary FreeCell usually starts with two or three aces near the surface: you bank them, the columns get shorter, and the game opens out. Here there is nothing to bank at all. The first twenty moves are pure excavation, and a player who opens by parking cards in cells out of habit will be locked out before anything reaches a foundation.
This is the whole game in one sentence. Four empty cells give you a move limit of five, which is enough to shift a substantial run in a single action. Spend a cell on a card you have nowhere to put and the limit drops to four, then three. In ordinary FreeCell you can afford that because banking an ace buys the room back; here nothing gets banked for a long time, so every cell you fill is gone until you dig your way out.
Because the aces are at the bottoms, the shortest route to a foundation is to strip a column completely. Choose the column whose upper cards have the most legal homes elsewhere — not necessarily the shortest one — and work it down. Half-digging three columns leaves you with three awkward boards and no foundation cards.
Any card may fill a space in this variant, so an empty column is genuinely flexible working room, and it doubles your move limit. Since a fully excavated column gives you both an ace and a space in the same instant, that first column is worth an enormous amount of effort. It is usually the move that decides the deal.
Burying the twos as well as the aces is what makes this variant bite. Banking an ace does not open the suit if its two is still at the bottom of another column, so plan for pairs: an ace whose two is sitting under six cards is worth less than an ace whose two is already loose.
With four cells free you can move five cards, or ten into a column that is not itself the destination. Check the number before committing to a transfer. Getting halfway through a six-card move and stranding the remainder in cells is the most common way a promising Challenge deal collapses.
Everything is face up, so the deal is a solvable puzzle with no hidden information. The strongest way to play is to explore a digging line several moves deep, see where it ends, undo back and try the other column. A lost position here is nearly always a decision made ten moves earlier.