What's particularly good: You must also figure out where the entrance and exit are.
Also good: there are plenty of easy levels to solve. The graphics are very good. The tutorial is helpful for novice puzzlers.
What's not as good: there's a weird system of earning stars that doesn't make much sense. Not that that's important anyway.
Also not so good: on the harder levels, you can figure out parts of the path.....but eventually you will have to do some guess & check. When you do that and want to backtrack, there's no proper undo button; you may as well just start from scratch.
What's good and bad: Over 1000. levels. Perhaps you want that. Too many for me.