"Each player starts with the same basic pistol. Every time you kill an enemy with your gun, you're upgraded to the next weapon. Anyone killed with a melee attack is demoted to the previous weapon, so watch your flank. Suicides also set you back to the previous tier, most often occurring when using explosive weapons. The match ends when someone cycles through all twenty weapons. Success in Gun Game requires aggressive tactics and familiarity with each weapon in the rotation. Don't worry about dying - just go for a lot of successive kills. "
Direct suicides with a weapon will result in a demotion. By definition, this means being caught in the blast of an explosive weapon's splash damage. Suicides by car bombs or red barrels will also demote the player, but suicide by fall damage will not.
If the player kills someone else by blowing up a car with a launcher, they don't advance to the next tier.
Double kills with a weapon don't advance the player two tiers.
If the player kills someone with a launcher and then kills themselves, they will go back one tier. However, if the enemy damaged the player before they killed themselves, the other player will get an "Assisted Suicide" kill, but will not advance.
Kills from the grave (afterlife kills) will advance the player a tier.
The console codename for Gun Game is gun.
David Vonderhaar, the design director for Treyarch, states that the idea for this game mode came "straight from the community," which was a thread created on their own Community Forums. Gun Game had an overwhelming demand from the majority of the community.
In Ghosts, the first sixteen weapons are randomized within their class, with random attachments. The player can view their current weapon and attachments by selecting Change Class in the menu. However, the assault rifle at thirteen will always have no attachments and the shotgun at fourteen will always have the Slug Rounds attachment in conjunction with a Red Dot Sight.
Gun Game seemed to have been planned to be released as a game mode in Call of Duty: Advanced Warfare, as in one issue of Newsweek Magazine, it was included with a list of game modes in Advanced Warfare; in addition, audio files for the initial start-up exist.