Played about an hour before I had to go to work myself. Can't wait to get back to it. I played as Link, who I've always kept in my rotation, and the Villager, who is the newcomer I was most excited to try. The other 3 characters you can pick it the demo are Pikachu, Mario, and Mega Man. The only stage available is Battlefield, but you can change it to "final destination mode" to get rid of the platforms and items, which is what I did.
Impressions:
1) In general, movement feels somewhere between Brawl and Melee. Speed is in the middle, you can still jump pretty high, but "fast falling" drops you at Melee speed. Both characters I used controlled extremely smoothly, and the 3DS controls weren't a problem to use at all.
2) Link is just a beast. I've used him since N64 days, but in Brawl, I used some other characters more because he wasn't that great. He will definitely be back in at the top of my list. His dash attack looks like a jump attack from Ocarina/Majora, and is a serious kill move at ~90% damage. Basically all of his projectiles have been strengthened too. And this is all while bumping his speed up too. If you are a Link player, you're in for a nice surprise.
3) Villager is not great in the air, but I had a ton of success guarding the edges of the stage. Plant a tree on the edge, knock someone out to the side, cut it down as they are trying to come back. Got me a kill every time it connected. Also, his side smash drops a bowling ball that falls until it hits the ground, which is another great one to do standing on the edge. Side B shoots a rocket that is slow enough to dodge, but fast enough to force them to dodge, which can be used to set up some other attack that they don't have time to react for, which is very handy.
All in all, it exceeded my expectations. When I get home I'm going to give Mega Man a try. I had been lukewarm on the 3DS version, but after playing this, I may have to rethink that. Not sure I can wait til November for more of this.