I may be mistaken, but I think you folks made it impossible to win -- new tiles that spawn always have a tile that they can merge into, so there can never be a lack of moves available.
Agreed. I had it reduced to a single tile available, yet there was no way to win. Every new tile matched one above or to the side of it.
Co-developer here- Not quite. It is possible, but you have to have the right kinds of tiles in the right positions. I won't give away the algorithm, but I do know it can be beaten. Not easily, perhaps, but certainly possible.