If you've ever played a first person shooter then you know that you can tell the good guys from the bad guys by the color of a little triangle (or circle or hexegon or whatever) floating over their head.

Well they are typically red and green.

What if you are colorblind, you wouldn't be able to tell them apart.  I believe game designers are remiss for not taking this into account for nearly 8% of all males have some form of color blindness.  Males being the larger demographic for gaming, I think there might be some benefit to pursuing some usability improvements in the use of color.

It wouldn't be hard, just make it a setting that the user can change.  Done and done.