The "Sonic" platformers released during the 1990s were acclaimed and have been listed among the greatest video games of all time. "Sonic" was touted as a faster, cooler alternative to Nintendo's contemporary "Mario" game, "Super Mario World" (1990). According to "Kotaku" Zolani Stewart, Sonic's rebellious character was representative of the culture of the 1990s, "when the idea of individual rebellion seemed inextricably linked to consumer culture". Writing in "The Guardian", Keith Stuart observed that "Sonic the Hedgehog"s emphasis on speed departed from accepted precepts of game design, requiring that players "learn through repetition rather than observation" as "the levels aren't designed to be seen or even understood in one playthrough... "Sonic" is incorrect game design and yet ... it's a masterpiece." "Sonic 2", "Sonic CD", "Sonic 3", and "Sonic & Knuckles" were praised for building on the first game's formula; in 1996, "Next Generation" described the Genesis games as "the zeitgeist of the 16-bit era".