Call of Duty: Ghosts extinction guide

Classes and Skill Points 

Before you start on your alien assault, you will need to pick your class. There are 4 classes to choose from: Weapon Specialist, Tank, Engineer, and Medic. Each class has their own strengths and weaknesses, but it’s always a good idea to have at least one medic in your squad. Tanks are insanely powerful once they have fully upgraded their class (which doesn’t take long) as they can have twice the health and twice the melee damage.

Each time you play, you will earn XP for your number of kills, hives destroyed, etc. and you will gain levels. These levels are permanent and will carry over from game to game, the higher you get; the more items that you can unlock. Items such as sentry guns, different ammo types, and stronger pistols become invaluable later on in the run, so don’t expect to get too far in your early goings.

Aside from the XP you earn, you can also earn skill points. As you earn these, you spend them on any one of the six categories you have available. These are Class, Pistol, Ammo, Team Support, Strike Package, and Equalizer. Each of these categories has their own varying types of tools that will need to be unlocked as you progress through levels.

With each skill point that you receive at the end of a round--when a hive is destroyed--you can place it in one of the six categories to increase its effectiveness. Later slots will require two skill points to upgrade, but if you complete the challenges given to you, you will be able to earn two skill points per round. The challenges are randomly given at each hive and can range from easy—like kill 25 enemies using only assault rifles—to overly difficult—like keep your accuracy at 75% or higher.

When the challenges appear, it is in your best interest to try and complete them, especially early on when the game hasn’t ramped up the difficulty. Earning the two skill points at a time is required to get your skills up to where they will be needed as you enter the City section of the game.