USA: Infected has implemented character randomization to keep the look of the game new and fresh. Unlike most tower defence and strategy games, we keep up a good atmosphere by mixing up the characters appearance. This generally not only looks good but helps to improve player / character connection and allows you to quickly find a specified unit in the middle of combat.
Here are some of the character skins that are available:
More skins are coming soon. Unfortunately I could not show them all standing in a row due to resolution issues.
Thanks,
Matt