Acrobatics is the ability to perform specialized maneuvers which
require agility. But agility is not enough; acrobatics involves
using the entire body as a single unit, not as a collection of
Characters with the Acrobatics skill will be able to perform such feats as back or front flips, cartwheels, handstands, etc. much more easily than their untrained friends. More advanced stunts such as tightrope walking are possible as the character's acrobatic talents increase.
Attempting multiple feats in a single round would require that the difficulties be added. Attempting to continue a feat (eg. handstand or walking on hands) through multiple rounds would require a further skill check for each additional round.
Of course, these difficulties assume ideal conditions (dry, flat, non-slippery surface; lack of strong winds; nobody poking large sticks at the character). Under adverse conditions, there will also be negative modifiers assigned. These are left up to the judgement of the GM.