Oh, no, I mean SSB adventure mode.
And yeah, MP3 launching alongside Halo 3 will just be one big put-down fest of "It doesn't have online, it doesn't have four player, piss, moan, whine, b*tch."
Online SSB is the only thing out of Nintendo right now that could contend with Halo 3, unless of course NST has been working on a Wii FPS with full online, Wiimote control, etc. and no one has said anything about it yet.