Unlike its predecessor, "level evolution looks to be a huge focus this time around, and it works wonderfully, as our free-for-all fights were not only about person vs. person survival, but also a constant battle for an ever-changing position against a world that didn't seem to want us there."

My personal favorite as far as levels go has to be the Bridge of Eldin from Zelda, as it's a no-BS flat world that allows for the purist face-off I play the game for.

Source- http://www.techeblog.com/index.php/tech-gadget/video-super-smash-bros-brawl-challenger-approaching-part-2