$49.00 USD

NEW! Version 2 adds support for regular & rapid-fire Commodore/Atari joysticks, advanced 8-button control usage, and functions as a BackButton™ when in Genesis/Megadrive mode.

The Commodore 64 & 128 are notorious for the fact that many games work only on Port 2, while some games require Port 1. Furthermore, since there is only 1 button on a typical joystick, often the fire on the other controller is needed for another action.

The GenAssister™ joystick adapter solves this problem by giving you control of both ports from one joystick! Use a standard Commodore or Atari joystick along with the physical switch to ease swapping ports. Or, plug in a Sega Genesis/MegaDrive controller and take advantage of 8 button madness, including rapid, automatic, and alternate port fire, and a button for UP! If you use the attached cable to plug into a BackBit cartridge, you can change games while lounging back in your easy chair!

Note: Do not plug a Genesis/MegaDrive controller directly into your C64 as this can cause damage. The GenAssister™ safely converts signals to protect your C64.



Comes with this extensive feature set:

  • Interfaces Sega Genesis/Megadrive joystick safely with your C64/C128 (DB9 only):
    • START button toggles between port 1 & 2;
    • MODE button returns to menu when attached to BackBit cartridge via included cable;
    • “A” button performs fire on alternate joystick;
    • “B” button performs REGULAR fire;
    • “C” button mimics UP direction;
    • “X” button toggles automatic rapid fire;
    • “Y” button performs rapid fire (approx. 30 times/second);
    • “Z” button performs second fire button (first introduced with C64GS);
  • Physical switch allows toggling joystick ports with normal or rapid-fire Commodore/Atari joystick;
  • Extremely responsive, offering approx 25µs latency for Commodore joystick and 250µs for Genesis/Megadrive;
  • Provides 100% compatibility with sensitive CIA chips;
  • Built-in fuse provides safety from short circuits;
  • 3D printed ABS case;
  • BackBit is not affiliated with Sega or RetroBit brands.

Games with special function using “A” on GenAssister:

1942 (air loop)
1985 – The Day After (rotation)
3-D Skramble (pause)
Acid Runner (pause)
After the War (duck on second level)
Afterburner USA (rockets)
Annihilator I / II (smart bomb)
Another World (destroy enemies on screen)
Anter Planter (pause)
Apache Strike (firing rocket)
Arachnophobia (poison bomb)
Arcade Pilot (destroys everything on screen)
Arcana (choose weapons)
Ark Pandora (salto)
Arktyczne Polowanie (pause)
Armalyte (toggle remote tracking on/off)
Armourdillo (music/sfx)
Arnie (pause)
Asterix & Magic Cauldron (pause)
Atomic Robo-Kid (cycle trough weapons)
Aviator Arcade II (destroying everything on screen)
Ball Crazy (pause)
Barbarian II – Dungeon of Drax (entrance in caves etc.)
Batman The Movie (loading next level)
Battle Command (?)
Beyond the Ice Palace (summon spirit)
Big Trouble in Little China (pause)
Blackwyche (change item)
Blue Max (pause)
Bomb Uzal (map)
Bounce! (pause)
Bubble Ghost (pause)
Buffalo Bill’s Wild West Show (space needed to be pressed before and after playing any mini-game)
Bugs Bunny – Private Eye (mega flash)
Cabal (throwing grenades)
California Raisins (?)
Castle Master (fire or walk mode)
Castle of Jasoom (?)
Castlevania (music/sfx)
Cataball (pause)
Caverns of Eriban (pause)
Centipede (pause)
Chase HQ (turbo)
Chickin Chase (?)
Chimera (pause)
Chopper Command (pause)
Chopper Commander (pause)
Chuckie Egg II (reset to main menu)
Citadel (?)
Clik Clak (option menu)
Combat Crazy (self-destruction)
Commando (throwing bomb)
Commando Arcade (throwing bomb)
Compare (cancel last move)
Compare II – New Levels (cancel last move)
Contra / Gryzor (jump)
Crackpots (pause)
Crazy Cars III (speed boost)
Crypt, The (fire or walk mode)
Crystal Kingdom Dizzy (jump)
Cyberdyne Warrior (entering shop)
Cyberwing (matter bomb)
Dam Busters (reset to main menu)
Dark Side (fire or walk mode)
Defcom (changing weapons)
Denarius (shield)
Dizzy – Prince of The Yolk Folk (jump)
Doctor Who and the Mines of Terror (?)
Donald Duck’s Playground (pause)
Double Dragon (Ocean) (jump)
Double Trouble (pause)
Dragon Skulle (change item)
Dragon Spirit (reset game to main screen)
Dragon’s Kingdom (pause)
Dragonhawk (reset to main menu)
Dream Warrior (pause)
Driller (fire or walk mode)
Dropzone (destroying everything on screen)
Eddie Kid Jump Challenge (brake)
Empire Strikes Back (throwing tow cable)
Encounter (reset to main menu)
Enduro Racer (bike on rear wheel)
Energy Warrior (changing area ID
Enforcer – Fullmetal Megablaster (smart bomb)
Entombed (change action)
F18 Hornet (firing missiles)
Fantasy World Dizzy (jump)
Fifth Axis (reset to main menu)
Finders Keepers (pause)
Fiona Rides Out (pause)
First Strike (change weapon during flight)
Flak – The Ultimate Flight Experience (reset to main menu)
Flintstones – Yabba Dabba Doo! (pause)
Flyerfox (reset to main menu)
Flying Digger (shooting a bomb)
Flying Shark / Sky Shark (activates bomb on screen)
Fort Apocalypse (pause)
Fred’s Back II & III (slow motion)
Fred’s in Troubles (slow motion)
Fred’s Back (game in slow motion)
Front Line (pause)
Frostbite (pause)
Future Knight (selecting items)
Galaxian (reset to main menu)
Garfield – Big, Fat, Hairy Deal (pause)
Gates of Dawn (instructions)
Ghettoblaster (pause)
Ghostbusters II (changing items on first level)
Give my Regards to Broad Street (brake)
Golden Axe (special weapon)
Golf Master (scrolling screen to see field)
Goonies (pause)
Gothik (option screen)
Gradius / Nemesis (upgrading weapon)
Green Beret (flame thrower)
Gremlins (reset to main menu)
Gremlins II – The New Batch (pause)
Gryzor / Contra (jump)
Guardian I / II (reverse)
Gunfright (change view)
Harald Hardtooth (pause)
Hard & Heavy (select temporary invincibility or bombs)
Hard Hat Mack (drop rivet gun)
Heartland (reset to main menu)
Hektic (pause)
Hektic II (pause)
Henry’s House (pause)
Ho! Ho! Ho! (back to main menu)
Hyper Circuit (hypercharge smart bomb)
I-Ball (smart missile)
Ice Palace (options menu)
Ikari Warriors (throwing bomb)
Implosion (turn around 180 degrees when static)
Impossamole (power)
Impossible Mission II (choosing options)
Insects in Space (destroying everything on screen)
Into Oblivion (smart bomb)
Into the Eagle’s Nest (pause)
Iridis Alpha (progress status display)
Java Jim in Square Shaped Trouble (reset to main menu)
Jet Set Willy II (pause)
Jinks (shaking screen)
Jinn-Genie (reset to main menu)
Joe Blade (pause)
Joe Blade II (pause)
Joe The Whizz Kid (pause)
Judge Dredd (Melbourne House) (pause)
Juice! (reset to main menu)
Jungle Hunt (reset to main menu)
Jupiter Lander (thrust)
Katakis (sending and calling drone)
Key Finders (?)
Keystone Kapers (pause)
KGB Agent (pause)
Kinetik (?)
Knight ‘n Grail (map)
Krystals of Zong (pause)
Kwik Snax (pause)
Last Ninja 3 (change weapons)
Lazer-Force (destroys everything on screen)
Legend of the Knucker Hole (pause)
Leviathan (reset game to main screen)
Lifeforce (self-destruction)
Lightforce (music/sfx)
Little Puff in Dragonland (reset to main menu)
Macadam Bumper (reset to main menu)
Mad Balls (pause)
Mad Planets (pause)
Magicland Dizzy (jump)
Marauder (smart bomb)
Master of Magic (inventory)
Menace (space ship goes to lower left corner)
Metro Blitz (pause)
Mickey Mouse (changing weapon)
Microdot (activating Jumpdrive space)
Midnight Resistance (missiles/nitro)
Miecze Valdgira II (English) (pause)
Monty on the Run (jumping forward)
Moon Crises 1999 (pause)
Moon Crystals (pause)
Moonfall (thrust)
Moonwalker (to start each level after introducing picture)
Mr. Heli (music/sfx)
Mr. TNT (reset to main menu)
Mystery of the Nile (reset to main menu)
Myth – History in the Making (change weapons)
NATO Commander (?)
Nebraska Joe (?)
Nemesis / Gradius (upgrading weapon)
Neoclyps (pause)
Neutral Zone (pause)
Night Shade (pause)
Night Shift (changing tools)
Ninja (reset to main menu)
Ninja Spirit (change weapons)
No Mercy (rockets)
Nobby the Aadvark (music on/off)
On the Tiles (shooting)
Operation Wolf (grenades)
Orb (level-skip)
Out Run Europa (music on/off)
Out Run (US Version) (pause)
Outlaw (destroy everything on screen)
Pac-Man (Atari) (reset to main menu)
Panther (restart mission)
Parsec (bomb)
Pentagram (?)
Peter Pat Rack (changing background colors)
Platoon (drop bombs on first level)
Poltergeist (destroy everything on screen)
Powerama (pause)
Powerdrift (pause)
Prince of Persia (showing minutes left)
Protector II (pause)
Pyramid Puzzler (reset to main menu)
Quick Draw McGraw (level-skip)
R-Nest (pause)
R-Type (attach and detach The Force)
Raid over Moscow (going to hangar)
Rallye (pause)
Ranarama (active spell list)
Rastan (pause)
Reckless Rufus (pause)
Recon (pause)
Red LED (pause)
Renegade (music/FX)
Repton (nuke)
Rescue on Fractalus (pause)
Revenge of the Mutant Camels (pause)
Road Warrior (going to fuel station)
Robocop 2 (jump)
Rockford 8restart level)
Rox-64 (panic destructor)
Rupert and the Ice Castle (pause)
Rupert and the Toymaker’s Party (pause)
Rygar (pause)
Saboteur (crouch)
Saint Dragon (music/sfx)
Salamander (?)
Sam’s Journey (restart level)
Saracen (pick items)
Savage (music/sfx)
Schizofrenia (pause)
Sentinel (pause)
Shadow Dancer (magic)
Shamus Case II (map)
Sheepoid DX (destroy everything on screen)
Shinobi (ninja magic)
Shockway Rider (music/sfx)
Sigma 7 (fast scroll to the right)
Skate Rock (pause)
Skatin’ USA (reset to main menu)
Sky Shark / Flying Shark (activates bomb on screen)
Slapfight (upgrading weapon)
Sleepwalker (pause)
Slimey’s Mine (?)
Sly Spy Secret Agent (music/sfx)
Snokie (reset to main menu)
Solomon’s Key (?)
Space Harrier (pause)
Spellbound (menu)
Spelunker (ward off the ghost)
Spindizzy (stopping the craft)
Spitfire ’40 (changing between cockpit and command view)
Spitfire Ace (reset to main menu)
Staff of Karnath (changing spells)
Star Ball (pause)
Star Empire (music/sfx)
Star Paws (reset to main menu)
Star Raiders II (going to space map)
Starforce Fighter (pause)
Stealth (pause)
Steel Ranger (changing weapons)
Steg the Slug (game over)
Stellar 7 (?)
Stinger! (destroys everything on screen)
Strike Force Cobra (jump)
Super Pipeline II (pause)
Superkid (reset to main menu)
Superkid in Space (reset to main menu)
Supertrux (reset to main menu)
Supremacy (second fire-button)
Tai-Pan (entering options menu)
Tales of the Arabian Nights (pause)
Tanium (pause)
Tarzan (pause)
Task-F (loop)
Technocop (destroying everything on screen)
Telnyr II – The Golden Chalice (option menu)
Tenract I / II (smart bomb)
Terror of the Deep (game over)
Thing Bounces Back (music on/off)
Thunderblade (pause)
Thundercats (reset to main menu)
Tiger Mission (smart bomb)
Tilt (reset to main menu)
Time Machine (?)
Times of Lore (option menu)
Titanic Blinky (reset to main menu)
To Be On Top (go to main menu after game over)
Total Eclipse I / II (fire or walk mode)
Treasure Island Dizzy (jump)
Tropical Fever (pause)
Tropical Fever II (pause)
Turbo Charge (turbo boost)
Turbo Esprit (map)
Turrican I / II / III (power lines, wheel)
Tusker (pick up items)
Twinworld (change weapons)
Vampire (pause)
Vendetta (change weapons)
Vengeance (enter the in-game menues)
Warhawk (pause)
Warlok (pause)
Werewolves of London (reset to main menu)
Wheelin’ Wallie (pause)
Where’s My Bones (pause)
Where’s My Bones II (pause)
Whirlinurd (pause)
Wizard’s Doom (self destruction)
Wonderboy in Monsterland (opening doors)
Z (bomb)
Zoids (music/fx)
Zone Z (pause)

Games with special function using “Z” on GenAssister:

Navy Seals (pause)
Pang (pause)
Robocop 2 (jump)
Space Gun (select shooting sights)
Super Mario Bros 64 (jump)
Turbo Charge (speed boost)

Additional information

Weight 4 oz
Case Option

Red, Black


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