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APPLE IIGS · 320 x 200 · EIGHT FIGHTERS

Flatline The Shiba Circuit

A one-on-one fighting game for the Apple IIgs. Eight fighters, each with a home stage, a style and a special move, and the Grid for mirror matches. A one-player ladder up to the woman who runs the circuit, two players at one keyboard or on keyboard and joystick, and head-to-head over the internet through a CoGS card. An original soundtrack and sound effects through the Ensoniq.

Read the manual Meet the fighters
Flatline title screen: the logo over the Shiba skyline, with the menu
Head to head with CGS

Play next to each other, or around the world.

Two Apple IIgs machines, a CoGS card in each, one lobby room. Type a name and a room code on both, pick your fighters, and the match runs in lockstep over the internet with the same frame on both screens.

ACTUAL IIGS GAME PLAY (EMULATOR) WITH COGS

How network play works →
01

In the game

Every picture here is the GS screen, 320 by 200, sixteen colours a scanline.

Wade throws the Ice Break at Rook across Shiba Harbour
Wade's Ice Break on its way across Shiba Harbour. The cranes and the Marais-Rand hoarding are behind the fight.
Lady Marais lunges with the Fleche at Villa Nightfall
Lady Marais's Fleche, a 40-pixel lunge with the energy wand, at Villa Nightfall.
Two Sables at the Grid, one spinning in the Razor Cyclone
A mirror match goes to the Grid. Sable's Razor Cyclone, three cuts on the way across.
VS screen, Wade against Rook
The VS screen while the match loads. The portraits spin in and the names type out.
Vane and Rook at Highside
Vane at home on Highside, the Marais-Rand pool deck above the sprawl.
Knockout at the Souk, Lady Marais over Rodrigo
Knockout. The announcer calls it, then the winner's name.
Character select screen
The select screen. P1 picks, P2 picks, the arrows choose whose home ground.
Kessel's Dub Drop floor wave at Tabernacle
Kessel's Dub Drop sends a wave along the floor of the Tabernacle.
Lady Marais's ending on the beach
Win the ladder and your fighter gets their ending, typed over the beach at dawn.
02

The Shiba Circuit

The Marais-Rand house runs a fight every winter on the dime of Shiba's black market bio clinics. The prize is a clean identity, a new liver, and a way off the circuit for good.

Wade wants his access back. Sable wants the fee. Rook wants the man who burned the Kobo. Kessel fights for the cluster's debt. Kuro fights because the family says so. Vane has orders he does not remember taking. Rodrigo fights for the odds. Lady Marais fights to see if anyone can.

YOU WIN, OR YOU FLATLINE.

The Story page in the game, over the dimmed Highside painting
The Story page in the game (S on the title).
03

The fighters

Eight, each with a home stage, a style, and one special. Full move lists are in the manual.

Wade

WADE

29 · SHIBA HARBOUR
Dock boxing · Ice Break

Ran code off the docks until the wrong people noticed. Fighting his way back in.

Moves →
Sable

SABLE

26 · THE SPAN
Bladework · Razor Cyclone

Freelance muscle, mirrored eyes. Nobody has seen her blink. Charges by the hour.

Moves →
Rook

ROOK

44 · THE KOBO
Bar brawling · Surplus Arm

Keeps the Kobo and the peace in it. The arm is surplus. The grudge is his.

Moves →
Kessel

KESSEL

38 · TABERNACLE
Dub rhythm · Dub Drop

Tug pilot off the orbital cluster. Hears a fight a beat before it happens.

Moves →
Kuro

KURO

?? · VILLA NIGHTFALL
Silent guard · Guard Step

The family's bodyguard. One of many with the same face under the mask.

Moves →
Vane

VANE

41 · HIGHSIDE
Military CQC · Flash Kick

What the war left of a colonel. Someone else holds the leash now.

Moves →
Rodrigo

RODRIGO

33 · THE SOUK
Capoeira · Meia Lua

Fixer, smuggler, dancer. Sells you the blade and then the bandage.

Moves →
Lady Marais

LADY MARAIS

24 · THE CORE
Fencing · Fleche

Heiress of the Marais-Rand house. The tournament is hers. So are the rules.

Moves →
04

The stages

Each fighter's home ground, and the Grid for a mirror match.

Shiba Harbour painting
SHIBA HARBOURWADE
The Span painting
THE SPANSABLE
The Kobo painting
THE KOBOROOK
Tabernacle painting
TABERNACLEKESSEL
Villa Nightfall painting
VILLA NIGHTFALLKURO
Highside painting
HIGHSIDEVANE
The Souk painting
THE SOUKRODRIGO
The Core painting
THE CORELADY MARAIS
The Grid painting
THE GRIDMIRROR MATCHES
05

One player: the ladder

Eight fights, each on your opponent's home ground. Beat them to move on. The seventh is against yourself, in the Grid. The last is at The Core, against Lady Marais of the Marais-Rand house, who runs the circuit. Pick her and the final is Kuro at the villa instead.

Three difficulties. Easy reacts slowly and rests between attacks; Hard blocks most of what you throw and goes for its special. Lose a fight and you have ten seconds to continue. Win them all and your fighter is off the circuit for good, with what they came for.

How the ladder works →

Choose a difficulty
Step 1, the difficulty.
Win 1 of 8
The results. Beaten fighters are crossed off.
Continue? 4
Ten seconds to fight again.
Wade's ending
Wade's ending.
06

Two players, one keyboard or two machines

A joystick match
Keyboard against joystick. J on the title says which player has the stick.
The CoGS Network Game page
G on the title, when no card is in.

Two at the keyboard: P1 on the arrows with Z and X, P2 on WASD with G and H. Keys come straight off the ADB keyboard, so both players can hold keys at once.

Joystick support. Plug in an Apple II analog joystick and the title says so. It is read as an eight-way stick, button 0 punches, button 1 kicks, and the special is down, forward, button 0. It goes to P1 by default; J on the title hands it to P2, so one player can have the stick and the other the keyboard.

With a CoGS card in each machine, Flatline plays head to head over the internet, two Apple IIgs machines, any two fighters, any stage, through the Game Room at a2cogs.com. Press N on the title, type a name and a room code, or leave the code blank to take the next player in. The two machines run the same simulation in lockstep; the card carries the inputs.

Network play in the manual →

07

Under the hood

MachineApple IIgs, ROM 01 or ROM 3, 2 MB or more; 4 MB recommended. On 2 MB a match load can come back NO MEMORY at the VS screen; Esc to the title and pick again. Runs stock; smoother with an accelerator.
ScreenSuper Hi-Res 320 x 200, a palette per scanline band (the stage, the two fighters and the blood red share sixteen colours a line).
Simulation30 ticks a second whatever the frame rate does; 14 to 18 frames a second drawn. Hit, hurt and block boxes per frame.
FightersRendered from motion capture in Blender, toned to the GS palette, mirrored and compiled to code on the GS when the match loads.
SoundEnsoniq DOC: eleven songs (a title theme, one per stage, the Grid and the ending), an announcer, and the fighters' grunts, all on the chip's oscillators at once.
DiskOne 32 MB ProDOS volume. Each pairing of fighters is its own match file with both stages in it.
NetworkLockstep over a CoGS card through the Game Room lobby, three ticks of input delay.
VS screen, Wade against Rook
The VS screen covers the match load.
Credits page
Credits (C on the title).
08

Getting it

Released November 8, 2026. Flatline is free. It ships as one 32 MB ProDOS volume that boots straight into the game, GS/OS 6.0.2 with the game as System/Start. 2 MB works, 4 MB is the comfortable size; on 2 MB a match load can come back NO MEMORY, and Esc then the same pick again usually gets it.

CoGS card holders: Browse Disks on the card, Featured, Flatline. It streams from a2cogs.com like the rest of the catalog; nothing else needs to be in the machine. Card firmware 1.41 keeps the music playing through the match loads.

Everyone else: download the image and write it to a CF or SD card for a CFFA or similar, or mount it in an emulator.

Questions to [email protected].