You should barely be able to see a difference between the inner and outer colour. If you're on a laptop also make sure to adjust the viewing angle of your screen. Don't worry if you can't see all the colours, the game has built-in tolerance and will give your a perfect score if the colours are very similar.
We implemented a solution for players with colour perception deficiencies: each primary colour represents a shape, and the intermediate steps are represented by a morph between each shape. The shape is meant as a general guide to pick the right hue, you will still need to adjust the colour to get a good score. Let us know how it works out for you at firstname.lastname@example.org.
We're really sorry; We've put a lot of effort into making this game run on as many platforms as possible. Unfortunately, we are unable to cover all scenarios. The game works on Google Chrome, Firefox, Safari, Opera and Internet Explorer 9. If you try one of those and still have problems, let us know.
Thanks for your interest!
Mark MacKay — email@example.com