Somewhere in the universe, there is a beautiful planet called Twinsun. It is populated by four different races, which have been living in peace and prosperity, until a mad scientist Dr. Funfrock of the Quetch (human-like) race used his newly invented cloning and teleporting techniques to create an army of fearsome soldiers and become the planet's dictator. Twinsun's inhabitants have not lost hope, placing their faith in the old legend about the benevolent goddess Sendell who would save the world. However, Dr. Funfrock totalitarian regime forbade displaying any images of the goddess and her worship.
A young Quetch named Twinsen was just a regular fellow until he had a dream, which surprisingly involved the outlawed goddess. It seems that Dr. Funfrock was no stranger to mind control; in his opinion, even dreaming of the goddess was illegal, and he promptly ordered to put the perpetrator in prison. Now the unlikely hero must find a way to escape and eventually save his planet from the clutches of its insane ruler.
Little Big Adventure (Relentless: Twinsen's Adventure in the US) is primarily an adventure game with strong action elements. As usually in adventure games, the hero must talk to other characters, and collect and use objects. However, not all the problems have to be solved with dialogue and item manipulation. The player can activate four different behavior modes for Twinsen: Normal, Aggressive, Athletic, and Discreet. The first is used for peaceful exploration and conversations; Aggressive mode allows Twinsen to punch and kick other characters; Athletic mode must be applied when it becomes necessary to run quickly and jump; Discreet effectively puts Twinsen in a stealth mode, making it possible to sneak by hostile character unnoticed. While activation of a particular mode is often required to solve a problem, many situations can be dealt with in different ways.
The game universe is rendered with characters in full 3D, while the environment uses isometric graphic tiles. The CD version (which was released earlier than the floppy one) features pre-rendered animated cutscenes, audio music and speech; all these features are absent from the floppy disk version.