04-15-2013, 01:26 PM
You shoudl work with pixels of equal size instead of having huge and tiny blocks alike. It looks really odd.
Some of the colours you used could easily be replaced by others you used to reduce the number of colours - without changing the visual appearance for the worse.
The different colour ramps you have use differently strong contrasr - purple is really strong, green less and grey has only slight contrast. They should be more equal (increase the contrast of grey, decrease the contrast of purple a little or example).