A Love Letter to Der Riese

Survive the Factory

Power the facility. Link the teleporters. Reach the Pack-a-Punch. Then keep moving when the walls begin to close in.

Der Koloss rebuilds the rhythm of classic round-based Zombies for the browser: start with a sidearm and 500 points, repair barricades, open the factory a room at a time, buy wall weapons, spin the Mystery Box, collect perks, and turn ordinary guns into strange new machines. Every round becomes faster and less forgiving.

You can play alone, host a private online lobby, or join friends with a short lobby code or invite link. Co-op supports up to four players with in-game voice chat, character selection, revives, shared objectives, and a scoreboard. For experimentation—or a wonderfully unfair victory lap—the cheat menu can grant points, perks, Pack-a-Punched loadouts, wonder weapons, open doors, linked teleporters, or even an empty map to explore in peace.

The Giant’s Shadow

The original Der Riese—“The Giant”—arrived in 2009 and changed Zombies forever by introducing teleporters and the Pack-a-Punch machine.

Its fiction centers on a secret Group 935 weapons facility: a maze of laboratories, assembly floors, animal testing rooms, electrical traps, and teleportation experiments powered by Element 115. By the time the four soldiers arrive, the research program has collapsed into an undead outbreak and the factory itself has become the enemy.

Tank Dempsey, Nikolai Belinski, Takeo Masaki, and Edward Richtofen bring four radically different temperaments into that nightmare: the brash Marine, the boisterous Red Army veteran, the disciplined Japanese captain, and the brilliant scientist whose past is tangled through the machinery around them. Der Koloss recreates their combat dynamic through character selection, radio-style voice reactions, revive lines, round calls, Pack-a-Punch remarks, and wonder-weapon discoveries.

A Familiar Story, Retold

This version is not a scene-for-scene remake. It is an original browser interpretation of that classic factory fantasy—built around the same essential tension between occult science and blunt-force survival. The map’s title, “The Colossus Awakens,” imagines the facility as a dormant war machine: restore its power and you awaken everything still trapped inside.

How to Play

Use a modern desktop browser, a keyboard, and a mouse. Click into the battlefield to capture the pointer; press Escape to pause or release it.

Input	Action
WASD	Move through the factory
MOUSE	Look and aim
LMB RMB E	Fire / aim down sights (RMB or E)
R I	Reload / inspect weapon
1 2 Q	Select or swap weapons
F	Buy, rebuild, revive, or interact
V G X	Knife / grenade / Monkey Bomb
SHIFT SPACE C	Sprint / jump / crouch
T TAB ESC	Flashlight / scoreboard / pause

First-Round Advice

Use the knife while early zombies are weak, repair boards for spare points, and avoid opening every route at once. Find the power switch before committing to perks. In co-op, stay within revive distance—but leave enough room to train the horde when the floor gets crowded.

How It Was Made

Der Koloss was designed and built by Vesper as a small, independent tribute—part game, part technical experiment, and entirely a labor of affection.

The game runs directly in the browser with Three.js—no engine, no install, and no build step. Its map geometry, lighting, procedural weapon models, combat systems, zombie director, HUD, menus, multiplayer, and cinematic effects were assembled specifically for this project.

It exists in two versions. Version 1 established the whole game—the map, the rounds, the arsenal, the perks, the co-op—and was written with Kimi K3 as the LLM and OpenCode as the development harness. Version 2 kept every one of those systems and rebuilt what you see and hear on top of them; it was built with Claude Opus 5 inside Claude Code. Both are described below.

Almost nothing in Der Koloss was modeled in advance. The factory itself—every wall, stair, catwalk, and doorway—along with all 31 weapons, the Pack-a-Punch, the perk machines, the mystery box, the teleporters, the hellhounds, and the night sky over the courtyard is generated from code at runtime: a few hundred primitives, lathed, extruded, merged, and surfaced by shaders written for this project. There is no model library sitting behind any of it.

The exceptions are worth naming precisely. Two CC0 zombie meshes from Quaternius provide the only rigged skeleton in the game—the horde, the player, and the four co-op soldiers all move on it—along with two blood decals. Brick, concrete, rusted metal, wood, diamond plate, and dirt surfaces come from ambientCG’s CC0 packs; every other texture, from machined gunmetal to the chalk sketches on the wall buys, is drawn onto a canvas as the game loads. And every sound effect and voice in the game was made with ElevenLabs.

The project has a public codebase. The Community Edition of the source is published on GitHub at github.com/rishipr/der-koloss-ce, for anyone who wants to read how any of the above is actually put together.

Sound and Voice Design

All sound effects and voice design in the game were created using ElevenLabs, then selected and integrated around the timing of each interaction. The weapon library distinguishes standard and Pack-a-Punch fire, while reload stages, bolts, magazines, pumps, power-ups, teleporters, machines, footsteps, zombies, environmental beds, and character performances each have their own recordings. Version 2 remastered the entire catalog—see below.

The four voice designs aim to recover the immediately recognizable energy of the classic crew: Dempsey’s abrasive bravado, Nikolai’s thunderous humor, Takeo’s restraint, and Richtofen’s gleeful instability. They are original AI-generated performances written for this fan project, created to evoke the characters’ spirit without presenting them as official recordings.

“Beauty of Annihilation” is the original Call of Duty: World at War Der Riese song and was not generated with ElevenLabs. Its artist, writer, original 2009 appearance, and rights attribution appear in a dedicated section of the Asset Archive.

You can hear the complete catalog, compare upgraded weapon reports, and inspect the animated armory models in the Asset Archive.

Rebuilding What You See

Version 1 played correctly and looked like a prototype. Version 2 changed no room, no round, and no rule—it replaced the rendering, the models, the movement, and the mix.

The renderer became a full high-dynamic-range pipeline: ambient occlusion, raymarched volumetric fog carrying the moon and the factory’s working lamps through the dust, reflections that appear only where the ground is actually wet, motion blur that smears the world while leaving the weapon sharp, and depth of field when you bring the sights up. Exposure is measured on the GPU each frame, and the image is tone-mapped with AgX rather than ACES—so a muzzle flash desaturates toward white instead of clipping to an orange blob.

The arsenal was rebuilt from scratch, each weapon going from 8–15 boxes to between 75 and 156 meshes: hollow bores, perforated shrouds, machined steel, walnut grain, checkered bakelite, and a gloved hand with articulated fingers. The four soldiers stopped being recolored zombie models and gained distinct silhouettes, human proportions, and the actual weapon they carry. Zombies received rim-lit necrotic shading and bone-attached damage geometry—torn tunics, shredded hems, exposed ribs—and risers now claw their way out of the floor instead of sliding out of it face-down.

The camera rides critically-damped springs—stride-locked bob, mouse-lag sway, a dip on landing—with recoil on a spring of its own, so the sights recover to wherever you were aiming rather than wherever the shot left them.

Found, Not Guessed

Most of the work was diagnosis rather than decoration. The horizontal black lines across the floor were not a post-processing artifact—they were floor slabs sharing an exact edge, leaving a hairline through which the dirt plane below showed. The flicker down every doorway was three coplanar surfaces, because three modules had each derived the same coordinate independently. And the frame rate was being eaten by 65 active point lights, every one evaluated per pixel; a pool of eight now tracks the nearest and brightest, taking the game from 21 to 120 frames per second at higher resolution than before.

The audio told the same story. Forty-two of the 64 gunshots peaked outside their first 40 milliseconds—some with silence before the shot—which is exactly why the arsenal felt mushy. Every one now has its transient on the first sample, the library sits on a single loudness scale, and the master bus, which had been applying make-up gain after the limiter and quietly clipping the output, was fixed.

Each fix that could silently return was pinned by a test. The validator suite grew from 9 scripts to 16—one builds all 31 weapons headless and proves each is still a single connected object, another parses every shipped module after a stray backtick in a shader comment once killed the entire game.