2D Infinite Runner Toolkit is a feature complete and easy to use package giving you the chance to create endless runner games of any kind.

Webplayer | Video | Forum

Features:
o Making use of the new UI features
o Making use of the new Unity 2D features
o Full gameplay mechanics (movement, obstacles, powerups, scoring)
o Menu system (main, shop, pause, gameover)
o Dynamic layer based level generation (including Parallax Scrolling)
o Aspect ratio based resolution manager
o Mission and game progress system
o Mobile support
o Fully commented source code

It works with Unity built-in features and does not need any 3rd party tools to get it up and running.