"Twenty-seven thousand nuclear weapons. One is missing." The storyline of the movie based on Tom Clancy's best-selling novel of counter-terrorism comes to the GBA in the form of a 15-mission campaign, in which players lead a crew formed from the FBI's elite Hostage Rescue Team. With gameplay similar to the GBA version of Tom Clancy's Rainbow Six: Rogue Spear, The Sum of All Fears offers squad-based action featuring four character classes: Recon, Assault, Demolition, and Sniper. Mission teams consist of up to four operatives per scenario, with each character rated in stealth, aim, health, and reflexes.
The missions in The Sum of All Fears range from hostage rescue and infiltration to planting explosives and "sanctioning" terrorists. Light, medium, or heavy armor usage is based on character class, as is the arsenal consisting of primary weapons, like the OICW (Objective Individual Combat Weapon), Special Ops shotgun, sub-machine gun, and sniper rifle, as well as secondary weapons and equipment. Solo players can replay missions in a "Lone Wolf" mode using a single operative, after completing both the primary and secondary objectives in campaign mode. Up to four players can link via GBA cable for multiplayer action in either cooperative or adversarial modes.