Behind the scenes of our Halloween event for Thunder RP

It all starts on the morning of September 12th. An idea floated internally at Thunder Studio: what if, for Halloween, the server broke completely from its usual timeline? Not just seasonal decoration, but a real scenario, with its own rules, its own ending, and an atmosphere unlike anything the team had produced before.

That idea became Thunder Z.

What really happened at Human Labs

Before thinking about game mechanics, the team needed a story. Ours begins in the ultra-secret Human Labs facility, tucked away in the mountains of San Andreas, where scientists were working on an experimental virus: VX-13. A program born from a confidential agreement between the government and a foreign power, who would trade the virus for advanced military technology.

The transfer plan was simple on paper: an armored truck moves VX-13 from Human Labs to the port of Los Santos, where a clandestine ship waits. But while crossing downtown, the convoy is struck by a civilian vehicle at a major intersection. The impact destroys the cryogenic container's containment system. Within minutes, an invisible mist escapes and silently contaminates the entire district.

Within 24 hours, hospitals are overwhelmed. Fever, loss of control, violent outbursts, delirium, then sudden death: the contagion spreads at a speed no one anticipated, and soon engulfs the whole city.

The government immediately places Los Santos under quarantine. But it's already too late to contain VX-13, and the contagion keeps spreading through the city.

Today, the entire island is lost. The government has retreated offshore and classified the territory as a black zone. On the ground, factions have formed: organized survivors, scientists searching for a cure, armed groups who see opportunity in the virus, and increasingly persistent rumors of mutations.

It's into these quarantined ruins that the players of Thunder Z land.

One of the ruined districts players had to cross.

A month of development for an apocalypse

What was meant to be a one-off event turned into over a month of work for the team. Zombies had to be designed to react to sound and sight, tracking mechanics had to keep the threat from ever feeling fully predictable, and a loot system dropping every 20 minutes was built to keep players moving instead of holed up in a corner.

A loot drop over downtown.

The whole story unfolds alongside Thunder RP's main timeline, like a parenthesis: for the space of one night, San Andreas shifts into another narrative.

Mapping out the gas zone in northern San Andreas.

A gameplay loop built for survival

Players start at Fort Zancudo, where an NPC hands them enough to survive the first few hours. The rest is up to them: a few zones of the map stay safe from zombies, but outside them, everything has to be rented, crafted, or stolen.

Geared up and ready to head out into the outbreak.

The stated goal is to survive. The team also slipped in a quieter layer of design: a secondary quest for players willing to dig deeper and understand what really triggered the outbreak.

Custom outfits were also designed for the occasion, so survivors would look the part from the very first minute:

An ending with no mercy

The team wanted a clean conclusion, not just an "event over" message. In the scenario, it's the Government itself that decides to blow up San Andreas to put an end to the zombies. Players who managed to reach Los Santos airport in time make it out, with a takeoff cutscene. The others don't get that chance.

Sound as a throughline

An event like this is also felt through sound. The team built a distinct sonic identity for Thunder Z, from the loading screen to the closing credits, keeping the atmosphere consistent at every key moment of the experience.

Video

Thanks to Fraydolix for the VOD of the Twitch stream covering the event:

Thunder Z was a month of development for one night of Halloween, and a new testing ground for Thunder Studio in event storytelling and game design.