Gimpyfish, t!mmy, t0mmy, Neal, DSF, Lucky, MikeHaze, HugS, and many others including myself, attended the E For All event and found out multiple exploits in the game, such has Melee style Dash dancing, using the momentum of an aerial attack low to the ground to waveland (Mario, Fox, Samus, Sonic, Link = Bair, Pikachu = Diagonal quick attack into the ground / Platform), L-canceling, proper hitstun, charging smash attacks with the C-stick, Throws retaining Melee properties (Fox's D-this causing a tech chase and Peach's F-throw being a killing move), Crouch canceling. These specific things were removed from the game, but not entirely. If you do a bair low to the ground with Mario you will notice that he moves back slightly, but doesn't slide, but Peach can still slide with her down tilt and pulling turnips because we didn't discover it. Coincidence? Mario was also very good, capable of doing things like double sh bair, the first one hitting and the second one allowing him to waveland back and follow up with an up tilt to whatever aerial at high percents or jab to grab>d-throw> U smash at lower percents. Minus the Shine difficulty Fox was also very solid with his combos and ground game. Samus' super missiles knocked opponents strait up with a lot of stun, giving her some interesting set ups. Meta Knight was still pretty strong; his Drill Rush was his best move. There are many other things covered, and if you need reference, check these.
http://smashboards.com/threads/the-...ight-thread-and-general-mk-discussion.146853/
http://allisbrawl.com/forum/topic.aspx?id=2426
http://www.neoseeker.com/forums/32197/t1022156-brawl-tech-report-from-for-all-by-gimpyfish/
http://smashboards.com/threads/gimpyfishs-brawl-impressions-brawl-talk-episode-1-added.121329/
There are more too. But I'm planning on keeping what I know on the DL.