LogFAQs > #979191889

GuerrillaSoldier posted...

literally everything about this is wrong, even if you want to call it an "expansion pack"

Sonic 3 and Sonic & Knuckles were originally planned as a single game. However, the manufacturing costs of a 34-megabit cartridge[30] with NVRAM would have been prohibitively expensive.[31] Due to the game's scope and Sega of America's commitment to launch a major McDonald's Happy Meal promotion in February 1994,[26][32] the team reluctantly split it in half,[22][14] allowing more time to develop the second part and splitting the cost between two cartridges.

If this happened today people would rightfully point out how short Sonic 3 is compared to Sonic 2, and that Sega knowingly released an unfinished game, to "fix it later" with a planned DLC / expansion. There just wasn't social media to complain on back then.