Call of Duty: Modern Warfare 2/Perk 1

There are five perks available to use in the Perk 1 slot. For each of these perks, a "pro" version of the perk can be unlocked by completing its specific challenge. The upgraded perk's effects are combined with the original perk's effects, which means perks can give two effects from one slot.

Marathon allows you to sprint for an infinite period of time, this can be very useful if combined with Lightweight as it allows you to sprint very fast. This can be used to get easier knife or riot shield kills or alternately play as a flag runner in Capture the Flag. The pro version of this perk is not very useful. Levelling up this perk is easiest on game modes where you do a lot of running (Capture the Flag, Search and Destroy or Sabotage).

Sleight of Hand is a very useful perk. Almost all of the classes can benefit from the quicker reload (Especially LMGs and Shotguns). It also means that the player can change their secondary weapon as reloading is around the same speed (or faster) than reloading. The Pro Perk can help snipers quickscope (aim down the sights, shoot while going into the sights for good accuracy then quickly go back to hipfire mode). It can also be generally useful in gameplay for getting more accurate shots.

Scavenger allows you to resupply from packs found near to enemy and ally bodies. These resupply some of your ammunition and also your equipment and secondary weapons. This can be useful to obtain more grenades, claymores or C4 (even though you can only plant 2 Claymores or C4 at a time). The pro version means that you have full ammo for your gun every time you spawn, this means that you will not have to resupply a lot and can be very useful for campers which will not get into the main firefights. This perk can be very useful for classes that fight at close quarters and when the pro version is unlocked, it can also be used by campers successfully.

Bling can be very useful on most weapons as it allows two attachments, this means that you can have a silencer and a scope. This should allow your weapon to be used well in more situations. The Pro version also allows your secondary weapon to have two attachments, this can be less useful depending on the weapon that you pick and how much you use it. You should only use this perk on weapons that have killed more than 25 people so you have two perks to choose from. It can also be useful to gain two sets of challenges for weapons at the same time.

One Man Army replaces your secondary weapon, but instead of swapping weapons, you can swap classes, you can only do this once unless the class you swap to also has One Man Army on. It can be useful to quickly gain extra claymores or C4 at the start of a match by switching to the same class, it can also be used to re-gain ammo or grenades for the grenade launcher. Scavenger is normally a better choice as you are left defenceless for sometime with this perk. This should normally be used for campers trying to re-gain equipment or for snipers that swap to a close quarters class.