2. Sony PlayStation
Global sales: 102.49 million
Then again, Sega was considered a Nintendo-caliber gaming company right around the time Sony's PlayStation came onto the scene.
Sega and Nintendo had run neck-and-neck with their 16-bit Super Nintendo and Sega Genesis systems a generation earlier and Sega had put a lot of time and considerable capital into building its 32-bit Saturn. Nintendo had 32-bit plans of its own and partnered with Sony to make a disc-based add-on to the Super Nintendo. The folks at Nintendo didn't like the fact that a contract between the two companies gave Sony complete control over software titles made in the new disc format, but had plans to release a "Play Station" that played both new 32-bit discs and existing Super Nintendo cartridges as recently as 1992.
A lawsuit and resulting agreement finally divided the two companies, and the PlayStation went forward without Nintendo in 1994. Sony ended up more than doubling the sales of Sega's Saturn and Nintendo's ensuing, cartridge-based Nintendo 64 combined. The games got grittier, with gamers introduced to the dark horrors and terrible voiceovers of Resident Evil, the battlefield conditions of Metal Gear Solid, the near-arcade quality of Tekken 3, the racing realism of Gran Turismo and the long, layered quests of the Final Fantasy series. And memory cards were there to save all of it.
Sony did what Nintendo wouldn't do and what Sega paid too much to do with titles including Virtua Cop, Daytona USA and Virtua Fighter -- it grew up. It brought video games out of the realm of childish things and arcade nostalgia and into their own as a potent, grown-up entertainment option. It gave console gaming its hard core and set the stage for even greater growth.