Challenge

In Call of Duty 4, challenges are are given to the player in five tiers. Each one is more challenging than the other, and might take some time to complete. While the "regular" give out a meager 250 Experience points, the weapon-based ones can give up to as much as 1000 XP when they are completed. With the regular challenges, there is no physical prize to show, but weapon challenges give the player special attachments and camouflages to put on the weapon that beat the challenge.

List of Weapon Challenges

 * Marksman's Challenges
 * Expert Challenges

List of Challenge Tiers

 * Boot Camp
 * Operations
 * Killer
 * Humiliation
 * Elite