Equilibrium is company based in Sausalito, California. It all began in 1989 and the company is a selfclaimed pioneer and leader in development of imaging solutions. But before 1992, where they released the DeBabelizer imaging software, they actually did a bit of game development. Today there is no sign of these games anywhere on their website though. 
 

While most of their work was published by THQ, they also managed to get a foot in the door at Capcom, developing a football game for the Super Nintendo, called Capcom's MVP Football. Wile most of their releases happened on the gameboy, using the same game engine for all except the Bo Jackson Hit & Run game.

Most interesting though is that they also tried their luck with a few NES games, but only Peter Pan and the Pirates was released. Another two were completed but never went into manufacturing.

One was "The Flash". Development took around 3 months, from March to June 1992, where the project got scrapped. The game was actually a conversion of the Gameboy release from 1991. In charge of the project was James C. Fox and about the conversion project he says

I created assembly macros that mapped Game Boy Z80 instructions into appropriate NES 6502 equivalent instructions. I then emulated the Game Boy operating system on the NES. The final product actually ran quicker after the conversion. I utilized a NES emulator and 6502 assembler. James C. Fox

Unfortunately the conversion of The Flash happened around the time Equilibrium decided to quit the game development business and put all attention towards their DeBabelizer project. Most of the people working on game development were laid off and the Babelizer was released later that year.

The Flash was very close, only a few weeks away, from being finished. The programmer was laid off like the rest of the game development crew and as we know, The Flash for the Nintendo Entertainment System never happened.

Another unreleased NES game is Defectors, it plays a bit like Berzerk. Up to 4 players are allowed. The task is to shoot these small robots on the screen so they'll turn the color of your character, while doing this you have to avoid getting hit by robots with other colors and at the same time collect points, which are small glowing dots in the screen.

The game is quite addictive but yet very basic, graphic wise. The reason for this being that the game never left the Alpha stage and the existing copy supposedly only includes about 10 levels. As far as I know Defectors was never announced in any magazine or even displayed at CES or any other event, but samples were floating around, and a few years ago one of these samples surfaced in a box of scrap from American Video Entertainment. The game EPROMS were programmed in December 1990, so Defectors most likely isn't Equilibrium's first NES project, as Peter Pan was published by THQ in January 1991.

I managed to find the programmer of the game, who unfotunately didn't have much to add to the story other than what we already know - the game was never completed as he left early in the development. Other might have resumed the project before it eventually got scrapped though, but the game could have been an extremely fun multiplayer.

Below is a list of games developed by Equilibrium.

1990 Bo Jackson Hit & Run (Gameboy) - THQ
1990 Defectors! (NES ) - Unreleased
1990 Peter Pan and the Pirates (NES) - THQ
1991 Attack of the killer Tomatoes (Gameboy) - THQ
1991 Flash, The (Gameboy) - THQ
1992 Capcom's MVP Football (SNES) - Capcom
1992 Flash, The (NES) - Unreleased (Gameboy port)
1992 Road Riot 4WD (SNES) - THQ 
1992 Swamp Thing (Gameboy) - THQ