18 Puzzle is a variation of classic 15 Puzzle game. Not only does 18 Puzzle has 18 tiles to move (vs. 15 in classic Fifteen) but also 18 Puzzle uses hexagonal board making the game more challenging.
If 18 tiles is not challenging enough for you, you could always increase the size of the board and number of tiles to move or the other way around if 18 tiles is too much for you, make the board smaller.
Free competition edition is meant for competition, i.e. you have less then two minutes to solve the puzzle. If your need more time then consider buying 18 Puzzle for training.
Do check out our other games - "14 Puzzle" and "Magic Cylinder".