Rail Maze for the BlackBerry PlayBook comes in two varieties - a free version (which I have been playing) and a pro version which costs $0.99. Looking at the description in App World it isn't too clear what the differences are although I would imagine that with the free version once you complete a certain amount of levels it will prompt you to purchase the full edition.
Either way it is a fantastic game. As the name suggests, you must guide a train around the tracks from start to finish. However, you will need to change the track points to avoid the train going off the tracks or it will crash. The levels clearly get harder as you progress and when other trains also appear on the tracks it can get a little challenging to say the least.
If Rail Maze looks your cup of tea go grab the free version and give it a test. I'm loving it and I suspect I will be buying the pro version pretty soon.
Game features include:
3 game modes:
Solve 100+ of challenging and unique puzzles, build railroads, bomb through obstacles, escape PIRATES on rails. Have a lot of fun with this unique puzzle game.