Here's a sales list of all series repped in Brawl, basically.
Mario - over 200 million units sold (Dr. Mario is considered part of this series, as a spin-off)
Pokémon - over 160 million units sold
Tetris - over 60 million units sold
Zelda - over 53 million units sold
Game and Watch - over 45 million units sold
Donkey Kong -over 45 million units sold
Sonic the Hedgehog - over 45 million units sold
Kirby('s Dreamland) - over 30 million units sold
Wii Series - over 20 million units sold (several songs plus Miis can be your avatar)
Metal Gear - over 20 million units sold
Nintendogs- over 15 million units sold (Nintendogs as an assist trophy)
Metroid - over 13 million units sold
Super Smash Bros. - over 13 million units s old
Yoshi - Well over 10 million units sold (hard to tell, since Yoshi series sales are considered Mario series more then not)
Animal Crossing - over 8 million units sold
Brain Age - over 6 million units sold (it has a song or two at least)
1080 Snowboarding - well over 5 million units sold (it has a song, lol!)
Wario Land - over 5 million units sold
Star Fox - less then 4 million units sold
Fire Emblem - less then 4 million units sold
Balloon Fight - less then/about 3 million units sold (including spin-off; it has two songs; one from Melee)
MOTHER/EarthBound - less then 3 (probably less then 2 1/2 million) units sold
Pikmin - about 2 million units sold
Wario Ware - over 2 million units sold (note: there is a diffrence between the Wario Ware and the Wario Land series)
Kid Icarus - around 2 million units sold
F-Zero - less then 2 million units sold
Electoplankton - at least over 1 million units sold (a stage)
Mach Rider - over 1 million units sold (1 or 2 songs; 1 from Melee)
Ice Climber - over 1 million units sold
Shin Onigashima -Less then 1 million units sold (some old Japan-only Famicom series)
Panel De Pon - Less then 1 million units sold (it has a item, and a song)
X - Less then 1 million units sold (2 songs)
Nazo no Murasamejou - Less then 1 million units sold (it has a song; this is the game Takamaru stars
)
Several other NES series not mentioned - at most over 1 million units sold (there is a NES/Famicom song mix, with several NES/Famicom game songs on it)
I probably forgot a franchise via the NES/Famicom Medley, but oh well!
Ya, Kirby is overrepped. Donkey Kong not just is a better selling series, it was the best selling series on the SNES. Everyone knows Donkey Kong. Donkey Kong has less music, and 1 less character then Kirby, and it's a superior series saleswise (and gameplay-wise in my opinion). But Star Fox is overrepped the worst, BY A HUGE MARGIN! It's a minor series, while Metroid is a Nintendo flagship series. And to some degree, EarthBound/MOTHER and Fire Emblem are overrepped. Zelda is also overrepped, while Mario and Pokémon are underrepped. The Zelda series should have dropped that abomination of a minor character in Sheik a long time ago, while Pokémon keeps Mewtwo, but again, Sakurai is a failure at character choices. Mario is a superior series to Zelda. If you don't know who Mario is, or what the Mario series is, you arne't a gamer. MARIO IS GAMING! Give it Bowser Jr., Geno, Paper Mario, ANYTHING! Sheik is a minor character from a game that's almost a decaded old. Sheik made like what, a 10 minute appearance? Give us Midna, Vatti, or something, who actually play A ROLL in the sereies. Let Sheik die, already. Zelda, Link, Ganondorf, and Toon Link are enough universal reps, anyways.
Sakurai obviously doesn't know how to rep properly, AT ALL! He's obviously only knows who we wanted the most (King Dedede, Ike, Diddy Kong, Sonic the Hedgehog, Captain Olimar, Lucas, and Lucario), adds some intresting WTF characters ,but is otherwise clueless. Everything revolves around the SSE (the main theme, the opening, the characters), which really annoys me. Smash is about multiplayer, not the story. Well, at least Sakurai held back from giving us any uneeded Japan-only characters (Lucas was sort of needed). But seriously, Sheik returning, and no Mewtwo=FAILURE! Whoever thought of that doesn't know Sheik would be lucky to make Nintendo $20. Mewtwo has made Nintendo hundred of millions of dollars, is the strongest Pokémon, and probably the most popular after that abomination of a electric rat. I'd honestly would have rather have had Miyamoto make Brawl then Sakurai just because of that.
And Lucario is fairly fast, I suppose
