Combat Arms gameplay is similar to commercial games such as Counter-Strike, Ghost Recon 2 and Call of Duty.The game offers many different modes of play, including One Man Army and Elimination and variations with objectives, as well as multiplayer co-op called Fireteam mode and Quarantine mode. During winter, a special mode of Snowball Fight is unlocked. Combat Arms uses a player ranking system based on total experience, using common military ranks that players can obtain. Completing objectives, killing other players, and levelling up one's rank gives the player money in the form of Gear Points (GP), which can be used to purchase new weapons and accessories. All items purchased have a time length of anywhere from 1 to 90 days, after which the gear is deleted from the players inventory. Players can also purchase equipment from the Black Market (also known as Nexon Cash Shop) using NX that are bought with real-world money. Primarily, the Black Market equipment is cosmetically different from regular shop items and has no rank or level requirement that many of the free items require. There are some items that may be obtained only through the Black Market, including permanent weapons.


The game boasts customizability that includes female player models.
Combat Arms has over 3,000,000 registered players. The game supports community features such as clans and an in-game friends' list. There are currently no official gaming leagues.

Combat Arms closed beta started on May 29, 2008, exclusively through FilePlanet and ran until June 6. This beta was limited to users from North America, South America, and Oceania. In the closed beta, 4 maps and 30 weapons were available. On June 26, Combat Arms went into its Pre-Open Beta Phase, whereby the game was open to the public, but it was still being tested and changed to prepare for Open Beta. Pre-Open Beta was still limited to users from North America, South America, and Oceania. The Official Launch of Combat Arms started on July 11, 2008.
On the August 8, 2008, Nexon announced[6] that a Combat Arms service would be started by Nexon Europe for European Players. On September 25, 2008, the Combat Arms Europe Teaser website was activated by Nexon Europe, and on October 28, 2008, Nexon Europe started the Combat Arms Europe Closed Beta testing. Closed Beta testing finished on November 11, 2008, and the Open Beta testing began on December 16, 2008 and lasted until January 15, 2009. The game is now fully released in Korea, North America, and Europe. On April 2, 2009, Nexon America announced that South American service for Combat Arms will cease on April 9. Those who have any amount of Nexon Cash (NX) will be allowed to play until October 9, or until their NX falls below an undefined amount, whichever comes first.
On November 18, 2009, Nexon America announced that it would be teaming up with Vivox to provide voice chat to Combat Arms.A team from Vivox is moderating the use of this chatting feature in Combat Arms.