All folders in the lua directorie should contain the following files:
runner.png : a 4 times 4 sprite sheet. the first 12 images being a walk cycle, the bottom 4 a jump animation.
runnerSound.ogg : a sound beeing looped while the animation is playing
point.png : whatever the character wants to collect
portal.png : the entrance into your world ;)
At the start of the game a folder will be chosen at random, and that runner is loaded. If you collect 10 points a portal will appear and bring you to another world.