The easy mode is way too easy. We've seen this type of puzzle way too often.
The medium mode is slightly harder. Each tile has either 3 or 4 colors.
The hard mode is fantastic. And very hard. As you slide a row across, each tile rotates 90 degrees. So there are 2 tasks: solving for the position of each tile and the orientation. I've tried it only once and ran out of moves.
Similar Games (This list is very incomplete.)
Digits Square Puzzle Game
Flat Cubes a 2D Rubik's Cube