The game simulates infantry and combined arms warfare of World War II using a modified version of the id Tech 3 engine.

Much of its theme and gameplay is similar to the Medal of Honor series; however, Call of Duty showcases multiple viewpoints staged in the American, British, and Soviet campaigns of World War II in Europe.

The game introduced a new take on AI-controlled allies who support the player during missions and react to situational changes during gameplay.

This led to a greater emphasis on squad-based play as opposed to the "lone wolf" approach often portrayed in earlier first-person shooter games.

[5] As a first-person shooter, Call of Duty places the player in control of an infantry soldier who makes use of various authentic World War II firearms in combat.

The American campaign begins in August 1942 with Private Martin, a newly enlisted member of the 506th Parachute Infantry Regiment, completing basic training at Camp Toccoa.

Martin and his unit are sent to force the remaining Germans from Sainte-Mère-Église and disable several Flakpanzer IVs as D-Day begins.

Martin's unit destroys German artillery positions attacking the landing force at Utah Beach.

Afterwards, Martin learns that his unit has been assigned to participate in an attack on a Bavarian manor in August 1944 to rescue two British officers, Captain Price and Major Ingram.

The British campaign starts with Sergeant Jack Evans and a unit from 2nd Ox and Bucks of the 6th Airborne Division taking part in Operation Tonga.

Evans and Price then pose as German naval officers and sailors to infiltrate the battleship Tirpitz, disable its defenses, and steals information for the RAF to attack the ship.

In November, Voronin rendezvous with a unit led by Sergeant Pavlov, tasked with retaking an apartment building in German hands.

He and a small group of soldiers storm the Reichstag building and raise the Victory Banner atop the roof, ending the European war.

Led by Chief Creative Officer Vince Zampella, development began in April 2002, and the team grew to 27 members by May 2003.

[6] Using an enhanced version of the id Tech 3 game engine developed for Quake III Arena and an in-house skeletal animation system called "Ares", Infinity Ward set out to develop a new World War II-era video game that, unlike many of its predecessors, placed more emphasis on squad-based play with intelligent assistance from teammates during large-scale battles.

The team also extensively researched weapons, artillery, and vehicles from World War II to enhance the authenticity of animation and sounds used throughout the game.

The ability to suppress the enemy with cover fire and clear obstacles, such as fences and windows, was tightly integrated into the squad-based aspect of the single-player campaigns.

[2] Lead animation director Michael Boon explained that actions which would have normally been scripted in past games were moved to a dynamic AI environment, in order to help create a different experience each time levels are replayed.

An additional composition, "Age Of War" by Justin Skomarovsky, was commissioned for the intro cinematic leading into the "Call Of Duty" main title.

[28] Discussing this performance, Kristan Reed of GamesIndustry.biz wrote that "Activision will be pleased that it managed to interrupt the Sims party" with the game's release.

Its expansion pack - Call of Duty: United Offensive was developed by Gray Matter Studios and released September 14, 2004.

[35][36][39][40][41][42] More positively, the staff of IGN ranked the game number six in their 2024 list of the ten best Call of Duty games, writing: "While it's obviously a little out of date 20 years on, the campaign is still fun to play and it's impossible to understate the foundation it built for the future of not just the Call of Duty series but first-person shooters as a whole.