Aftermarket Junkie is an achievement or trophy (depending on your platform) in Far Cry 3. All you have to do is buy every attachment and paint job for a gun in the weapon shop. This can be done easily at the start of the game with the 1911, a pistol. There are no attachments and you can buy all these camo paint schemes for a total of $1200.
Atlas is an action-rpg with rogue-like elements where you use your ability to control the ground to fight the enemies and move through procedurally generated worlds.