1. Some boards have triangular and hexagonal cells.
2. According to the Leaderboard, there are over 25,000 players.
3. This game is far too easy. The 'Very Hard' levels are still very easy, they just have larger grids.
You're better off playing one of the games listed below. On the other hand, if you want something fast and easy, you can do these 200 levels in about 1 hour. Novice puzzlers would also like this.
Try these other Topology puzzle apps.
Lines Numeric Fun
Numeric Paranoia- Fantastic
Number Painting - Love this
Stroke! - Genius
Colors the Addictive Game
Chemin - Terrific
Flow Draw A Line
Link Mind Bending Puzzle - loved this
Tomb of the Brain
Flud - hard!
Roofbot - well polished and challenging