Solid Snake's inclusion in Smash Bros. Brawl's roster was not a random hat tip to the character, the series it came from, or even its creator. According to a couple of quotes caught by Joystiq, the inspiration for the ex-Fox operatives joining the Nintendo fray was due to Hideo Kojima's own son who expressed these sentiments to his father:
“My child likes Super Smash Bros., so we play it a lot together. And he told me that there’s no character that you made in that game.
As you know, we did make Twin Snakes, but generally speaking, there hasn’t been a lot of Metal Gear on Nintendo platforms. So from that perspective, I thought it was a good way to expose younger people to this character, Snake.”
It's no surprise, however, to learn that Kojima had already asked the game's director, Masahiro Sakurai back before Smash Bros. Melee was even released if his iconic sneaking star could be included in the game. Apparently, even after begging with Sakurai, Kojima was denied because the production was already too close to going gold (industry term for product being just about finished).
His unveiling for the next game though couldn't have been better, which can be seen below:
Who is your go-to character when playing Smash Bros. Brawl?