"URRRRAGHH! DAMNIT! I KEEP GETTING PWNED!! I just can't play this game."
"What the hell, dude."
My second son had come home from UCSD over winter break. We had just rebuilt one of his machines to modernize it for gaming. We had set up his rig in my office so he could relax from his double major (Physics/Math) and lab responsibilities by playing "Call of Duty: Modern Warfare 2".
I looked over at his screen. He was playing online in a team. Target identifiers in pastel green and pink flashed over other players as they popped in and out of view. How handy: IFF for grunts. Totally unrealistic and totally useless for my son.
Not profoundly, but with enough red/green confusion to make the transparent target tags indistinct, and especially indistinct when they briefly flash during a mêlée.
In-game avatars are unbelievably swift and jumpy. Coupled with lag and server processing time, it may be too late to aim and fire anyhow, and especially too late if a player's reaction loop requires him/her to figure out something's color.
The Real Problem
Between 5 and 10% of caucasian males are colorblind. Since most live in North America and Europe, their 18- to 34-year-old demographic is exactly who buys and plays games like CoD:MW2.
InfinityWard, CoD:MW2's producer, has knee-capped 1 in 12 customers.
It's just about unforgivable. Red-green confusion has been known since the 90s, that is, the 1790s. The US military started testing for it in the 70s, again, that is the 1870s.
To make matters worse, much of the in-game heads-up display renders info in reds, greens, and yellows with a high alpha blend, making them transparent. CoD:MW2 also places HUD items at the visual periphery of the screen. HUD placement and coloring makes them useless for colorblind players and difficult for everyone else, too.
Here's why: human peripheral vision has very little color sensitivity. Try it yourself: hold a small red or green colored lamp (an LED is ideal) a meter away and view it from the corner of your eye. I defy you to answer honestly what color it is when viewed from that vantage. It should appear somewhat yellowish-bright, nothing more. Now, try this experiment with the indicator lamps on your car's dashboard. You will appreciate (or despair) that the layout makes clear (or obscures) the meaning of each lamp.
Fixing the Design
Red-green confusion and its fixes are so well known that InfinityWard's design lapse is astonishing. This defect should never have made it to the marketplace — unless, of course, the company has a military contract to discover who's unfit for duty.
An easy patch: replace green with blue.
Next easiest: make a distinct mark or shape part of the target HUD; don't require the viewer to read it. There's a reason why financial statements indicate negative numbers in parentheses: they jump out without color.
Ensure peripheral information displays distinctly so it works from the corner of the eye. On a single screen, where the focal area and attention are close, vision detects color and shape reasonably well. As screens enlarge or become multipanel as in AMD's Eyefinity, moving visual cues outward will significantly degrade their color visibility.
And know the market. Don't kneecap your customers.