Sometimes people who didn't play the game will not understand what the strip is talking about and I am ok with it because you can't make a joke about something without pointing something which happens in the game.
However, least I risk people think I am suddently promoting weed t-shirts, I will explain this one:Modern Warfare have personal signatures called "callsigns". These callsigns have the player nick, a background and an image.
One callsign have weed leaves, surprisingly or not, you find people wearing it -a lot-... make you feel like you are fighting for (or against) an army of pot-heads trying to secure the biggest joint ever.
Fun enough, this isn't the topic of the comic, but how a plastic shield and a knife can beatautomatic rifles. World War III will have lines of knife throwing marksmen with columns of tower-shield wearing soldiers. It's like the medieval age all over again.