Exclusive to the 3DO version, in the level "The Project", there is a secret exit in the bottom-left corner of the map with a Question Mark caption just before it reading:


Entering this secret exit will boot up a 3D side-scrolling shoot-'em-up level. The game gives you 5 credits and 3 hit points to play through the game. You can pick up remote controls, and after getting enough of them your ship will now have triple shots. For every enemy shot at, the score will change to different quips and numbers at random, including:

•"69 Dude!"
•666 (the Number of the beast)
•90210 (the zip code to Beverly Hills, California and a reference to the 1990 television series "Beverly Hills, 90210")
•"Googleplex" [sic] (Googolplex, the company Google did not exist at the time this demo was made or when Gex was first released)
•"Really high!"
•"Way up there"
•"Astronomical"
•Infinity
•"Score is cool, huh, huh"
•"Are you still counting?"
•"I don't know"
•"I lost count"
•"Who cares!"
•"Who keeps score!"
•"Missed one!"
•"Watch your butt not the score!"
•"Is your controller plugged in"
•"Loser!"
•"You suck!"
•"Sucks to be you!"
•"How bad are you?!"

It was originally a senior college project for Stanford University by programmer Evan Wells, but was repurposed as an Easter egg for this game. On the Game Over screen, the game's credits can be seen:


This Easter egg was first known to have been documented in a pair of grainy YouTube videos from 2007. It's unknown why this minigame was not included in other versions of the game.