Only One Sega Genesis Game Had A Colored Variant Cartridge
Physical video games are largely a thing of the past. Though gamers can still obtain physical copies of games through traditional stores or online retailers, the physical game market accounts for less than 20% of all video game sales these days with most video game enthusiasts preferring to purchase their favorite titles digitally through online marketplaces (per Statista). However, in previous generations of gaming, physical copies were the only option. These physical games came in various types, be it discs or cartridges. One example of the latter for the Sega Genesis — a console that produced many classic titles such as "Mortal Kombat" and "Sonic the Hedgehog" — stands out as unique, even if it's only for the aesthetics.
For anyone that doesn't remember, Sega Genesis games didn't really vary in terms of physical presentation. Outside of the sticker that came on the game, usually adorned with its official artwork, most Sega Genesis game cartridges were black with no distinguishable characteristics. This means that pretty much every game that was released for it has somewhat of a sameness about it, physically speaking. However, there is one Sega Genesis game that has two existing cartridge colors.
Maximum Carnage had red and black cartidges
In 1994, Software Creations developed "Spider-Man and Venom: Maximum Carnage," a side-scrolling beat-'em-up based on the titular villain from "Spider-Man." Published by Acclaim Entertainment and released for both the SNES and the Sega Genesis, the game initially received mixed reviews when it first came out. Today, however, "Maximum Carnage" is widely praised and has even been considered to have changed the superhero beat-'em-up genre forever (via CBR). Outside of its modern reevaluation in the eyes of critics, there's something else that makes "Maximum Carnage" special — its Sega Genesis port had two differently colored cartridges.
When it was first released, both the SNES and Genesis versions of the game had distinct red-colored cartridges. This was highly unusual for Genesis games that typically came in black cartridges with stickers on them. Later printings of "Maximum Carnage" would come in the traditional black cartridge. While unique-colored game cartridges in and of themselves weren't a wholly unique thing, the red and black "Maximum Carnage" cartridges give the game the odd distinction of being the only Sega Genesis game to have been published with two different cartridge colors (per GamesRadar).
Despite "Maximum Carnage" being the sole example of a Genesis game having two different colored cartridges, they are relatively inexpensive. The original red cartridge can be found for as little as $30, while the black edition can be found for $18 on eBay.