5. Sega Genesis 1989
Sega took the gloves off with the release of the Genesis, not only beating Nintendo to the era of 16-bit graphics, but by featuring games like Mortal Kombat, the type of game that players had only dreamt of. The mature game was so controversial that Sega started rating their own games, warning parents while still being able to ship mature content. It was a move Nintendo had to copy in order to compete, while the likes of Sonic the Hedgehog gave even Mario a run for his money as the coolest mascot.