Wall jumping

The Wall Jump is a character-specific technique that some characters, such as Mario and Sonic will be able to use in Super Smash Flash 2.

The Wall Jump originated in Super Smash Bros. Melee and is performed by jumping into a wall and then pressing the jump button again. Doing this over and over will allow your character to ascend to new heights.

This technique was greatly nerfed in Brawl in that overuse of the technique would lessen distance and eventually cause a character to lose altitude. It is currently unknown if this measure will be implemented in SSF2.

Trivia
and were both able to wall jump in SSF2 demo v0.8b. However, there were no wall jump animations, Pikachu could do only one, Sonic's got weaker every time he wall jumped without touching the ground (Brawl style), and they could do it only in Central Highway and Twilight Town. In v0.9, Sonic and Pikachu can only wall jump on Central Highway on the right side of the bridges. Their is a glitch that makes Sonic wall jump on one of the bridges that disappears making it look like he is wall jumping off the air.

This can be seen here: http://www.youtube.com/watch?v=VDIaGwhmgcE