X-Tension

X-Tension (2000) was released as an expansion to X:BTF; however, many gamers and reviewers consider it more a sequel than an add-on" It follows on after the story in X: BTF, with "the evil Xenon vanquished" and the player "still stranded light years from home." The player once again takes control of Kyle Brennan, who now has "time to kill" as his X-perimental ship is reverse-engineered. The player is given a ship, some credits, and left to make his own way in the X Universe.

Gameplay
There is no over-arching plot in X-Tension. It is an open-ended, sandbox game, filled with "microquests". The player is free to choose "to be a trader with an unarmed Argon Lifter... or a bounty-hunter ... armed to the teeth with plasma throwers."; free to choose "where [they] want to go, what to trade in and who to pick on". Egosoft's Managing Director, Bernd Lehahn, described X-Tension as "[a] space game that allows you to live freely in a virtual universe and do whatever you want to do. At least that's our goal."

Changes
The graphics were improved for X-Tension, adding new effects and scenery, and removing "visible seams which blighted many of these backdrops in the original game.". The musical score was also extended, and the X Universe was expanded to a total of ninety systems.

X-Tension addressed many criticisms of the original game. The player's craft is pre-equipped with some upgrades - weapons and a time-accelerator - so that players can defend themselves from the beginning, although the weapons you start out with are useless against most of enemy ships. The player can leave the ship and space walk in a space suit, purchase new ships from shipyards, and even capture enemy ships that can be flown by the player.

The in-game interface was expanded to include new features, including an automatic navigation system that allows the player "to easily access information about any sectors" visited, and includes "a full map of the galaxy showing everywhere you have been." When combined with some upgrades and equipment, this system allows the player to monitor the X-Universe's economy, traffic and prices remotely, "an incredibly useful new feature which makes trading far less hit and miss than it was in the original game." The interface also allows the players to control many of their assets - factories and ship tasks - remotely. They no longer need to land at a factory to adjust it, nor even to be in same region of space.

One criticism shared by both games was the combat system; while improved in X-Tension, it could still be summed up as "unremarkable." Notably, Egosoft's Managing Director, Bernd Lehahn, mentioned appealing to "the 'Wing Commander audience'" as a high priority in the design of 2005 sequel X3: Reunion. He defined this as "people who... expect a story and cool fighting missions" but who may be won over to "the freeform gameplay and the advantages that a realistic economy adds to such a game."