Complete all 15 levels by giving the correct answers and get to the end. Pretty simple.
Solve the challenge within each level. This would yield you the name of a color. Type it in the answer box at the bottom of the page and click Submit beside it to check your answer.
If your answer is correct, you'll immediately move on to the next level.
As long as you completed at least Level 1, there should be a Resume button right next to the Start button on the front page when you come back. Click that and you'll be sent to your last unsolved level!
If you're switching between devices (e.g. your computer and phone), or if you reset your cookies often (e.g. browsing in Incognito Mode), you can bookmark the level page you're on and come back later.
The Color Riddle © Peso255