X-Tension is an expansion pack to X: Beyond the Frontier. The Earth pilot Kyle Brennan has vanquished the evil Xenon, and now finds himself stranded in space, light years from home. His "X-perimental" ship is reverse-engineered, and, with some credits in hand, he has nothing else to do but to kill some time.
Unlike X: Beyond the Frontier, there is no main plot in the game. The gameplay is open-ended; the player is free to choose to be a trader or a bounty hunter, and undertake any missions and quests in any order.
The expansion pack contains several new features. The player's craft is pre-equipped with weapons and a time-accelerator. The player can leave the ship and space walk in a space suit, purchase new ships from shipyards, and capture enemy ships that can be navigated later. The interface adds an automatic navigation system that includes a map of the galaxy. When certain conditions are met, the player is also able to monitor the economy, traffic, and prices in the X-Universe. The new interface also allows the player to control factories and ship tasks remotely.