Link - Mind Bending Puzzler from Akshay Kapoor is nothing new. The object is to start at 1, pass through all the numbers and then end on the highest number. No need to cross over every single square in the grid.
The most similar puzzle apps include Numeric Paranoia and Number Painting (see links below).
There are 200 levels and I'm somewhere around 120. Level 100 was the hardest so far.
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