The player helps him along his journey across "the world of air".
Balloon bears a heavy resemblance to the hot air balloon from Nitrome's first release, Hot Air. Unlike Hot Air, Balloon is supposed to be a standard helium balloon rather than a hot air balloon. It also has no driver, and its bottom has just one blue string.
The Balloon set off on an adventure across the World of Air. It completed its adventure, and so that others could experience the same adventure, it started the Hot Air Balloon Travel Company.
Other than ascending quickly and moving left or right depending on the controls, balloon possesses no other significant abilities. One might note that hazards and enemies only affect Balloon's "head", rather than the string. Contact with any enemies or hazards will cause him to lose a life, unless he has no more, of which he will then pop.