The design challenge rating system is based on 5 core design principles, which can be used to judge the effectiveness of a given design. Each principle (listed below) is graded on a scale of 1-10, 10 being the best.
The percentage score is an overall accumulation of the 1-10 rating you received for each of the 5 core design principles. So for instance, if percentage score is 50%, it means you accumulated a total of 25 points on the 5 design princiles.
A percentage score that's green means passing. Red means failing. You must get 50% or above to get a passing score.
These are all of the core elements that you need to concern yourself with, while you're designing. Nail these core elements down, and you'll have a high score.
One winner is chosen and will receive the stated prizes associated with the challenge.