The biggest shooter in the world is going through some big changes.

During a reveal event in Los Angeles, Activision (ATVI) and developer Treyarch took the wraps off “Call of Duty: Black Ops 4.” Due out October 12 for consoles and PC, the sequel to 2015’s “Black Ops III” strays from tradition by ditching the franchise’s standard single-player story campaign.

In its place, Treyarch will follow in the footsteps of recent mega-hits like “Fortnite” and “PlayerUnknown’s Battlegrounds” with an online battle royale mode called “Blackout.” Players will drop onto a huge map — 1,500 times bigger than the popular Call of Duty “Nuketown” map — and use their wits, weapons and vehicles to try to outlast the competition.

The decision to strip out the campaign will doubtlessly raise the ire of the fickle gamer community, though it’s clear that Activision sees the popularity of the burgeoning battle royale genre — and the ability to monetize a game far beyond its initial launch — as a rabbit well worth chasing.

Black Ops 4’s multiplayer focus was driven home by Treyarch chairman Mark Lamia.

“Call of Duty: Black Ops 4 gives you more ways to have fun with friends than anything we have ever created,” he said. “It’s the deepest, most replayable game in our history.”

It’s also a return to the boots-on-the-ground action that once defined “Call of Duty.” In recent years, the franchise moved into near-future settings, letting players jump thrust and wall run around levels. That kind of sci-fi mobility has been toned down in favor of more traditional running and gunning.

The new game introduces a slew of changes to that formula, however. Players will be able to heal themselves in the middle of a firefight, though they’ll need to be smart about when to do so.

Specialist classes grant unique abilities, including a grapple gun that lets a player quickly skim across the map, a radiation bomb that doles out area-of-effect damage, and recon sensor darts that show enemy positions. And longtime players will appreciate the inclusion of “predictive recoil,” a feature that makes it easier for players to master the nuances of the game’s varied munitions.

Activision is throwing a bone to story mode fans by weaving narrative elements into multiplayer itself. Each Specialist class will have story-based solo missions and trials to flesh out the game’s narrative context.

Story will also play a big role in “Black Ops 4’s” Zombies mode, which returns with three standalone, fantastical maps at launch. One sets its four characters in a gladiatorial arena, attacking the undead with axes, swords and hammers. Another takes place on the Titanic — yes, that Titanic — as it careens towards its icy destiny. And the third, set in a prison, is a callback to the popular Mob of the Dead map from “Black Ops II.”

A hands-on demo at the reveal event showed off the game’s standard multiplayer modes — Control, Domination and Hardpoint — and within minutes it was clear that mastering the new heal mechanic and learning the ins and outs of each Specialist’s gear is the difference between life and (repeated, embarrassing) death. Matches are fast, tight and exciting.

Running at a steady 60 frames per second, it’s a real stunner on the PC, though that’s expected on the smallish classic “Call of Duty” maps. Whether or not Activision can get that kind of performance out of a Battle Royale mode remains to be seen, as Blackout was not on display at the event (nor was Zombies).

Despite the incredible success of competing online shooters like “Fortnite,” “Overwatch,” “PUBG,” and Activision’s own “Destiny,” “Call of Duty” has remained surprisingly resilient over the years. Last year’s “Call of Duty: WWII” was the top-selling game of 2017 in North America — the ninth straight year the franchise has managed to top the region’s sales charts. Activision hopes “Black Ops 4” keeps the streak alive, but with EA’s fellow shooter “Battlefield V” and Rockstar’s eagerly-anticipated “Red Dead Redemption 2” expected to release alongside “Call of Duty” this fall, it won’t be an easy victory.

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