Chillingo has released Cogs for the iPhone and it one of the best value puzzlers on the app store at this time. It is seriously good and will keep you going for hours and hours and…

Cogs is a puzzle game where players build machines from sliding tiles. Players can choose from 50 levels and 3 gameplay modes. New puzzles are unlocked by building contraptions quickly and efficiently. A polished 3D look coupled with challenging gameplay and loads of level packs let you stay flummoxed for hours!

Inventor Mode: Starting with simple puzzles, players are introduced to the widgets that are used to build machines — gears, pipes, balloons, chimes, hammers, wheels, props, and more.

Time Challenge Mode: If you finish a puzzle in Inventor Mode, it will be unlocked here. This time, it will take fewer moves to reach a solution, but you only have 30 seconds to find it.
Move Challenge Mode: Take your time and plan ahead. Every click counts when you only get ten moves to find a solution.

A total of 51 levels are available with 11 available in the initial purchase and each next 10 pack available via in app purchase for $0.99.