Stage Select:
I've seen two approaches to this question: actual gaming figures and gaming characters.
If we do the former:
1. Shigeru Miyamoto. Probably the single most powerful individual in video gaming.
2. Hironobu Sakaguchi. Popularized RPGs into the mainstream. Not to take away from the likes of Richard "Lord British' Garriott who did a lot of the early pioneering work in the genre.
3. Nolan Bushnell, founder of Atari. He didn't invent video games, but he did bring them into the mainstream.
4. Kojima. I'm not as big of a MGS fan as other people here, but Kojima has earned his place.
For characters, I'd put up Mario, Link, Pac-Man, and Sonic. Those four characters put a recognizable face on gaming, but I realize that others might think that Geralt of Rivia, Snake, or some other less cartoonish character might be more appropriate.
Chrono Crossing: Although there were great games like TMNT, Dragon Warrior, and Faxanadu released this year, I'm going to go with Super Mario Land for the Game Boy. Sure, it was a half-sized Mario with a lot of weird concepts that never made it into mainstream Mario canon. The reason why it sticks out to me is that in 1989, it was incredible for 11-year-old Andrew to be able to play a handheld Super Mario game. The Game Boy was one of my favorite Christmas presents of my entire life. I still have my old Game Boy that's now nearly 30 years old. I guess the "correct" answer to this would be "Tetris," which is more universally known and could be argued to have more universal appeal. But the novely of Tetris has been long gone for me, while Mario is still as awesome as ever. I have a PS Vita and a 3DS now, plus every handheld that Nintendo ever made... but Super Mario Land was a miracle of technology in a time when most portable games were of the primitive Tiger/Game & Watch ilk.