Call of Duty (commonly abbreviated CoD) may be immensely popular, but the series is far from perfect. As Ryan Evans points out in his delightful parody, cheekily titled Cod of Duty, a lot of standard FPS campaigns are "short, not terribly interesting, and completely over the top with their story elements." Cod of Duty begins in a forest, where you're given a pistol and instructed to "leave no fish alive" because the evil cod are planning to destroy a nearby town. The title was created as part of the One Game a Month challenge — which explains its simplistic graphics — and the game's humor make it very worth the 15 minutes it takes to play. You can download it for free for Windows, Linux, and OS X, or play it in-browser on Evans' site.