Deus Ex: Human Revolution - The Missing Link is a DLC (downloadable content) for Deus Ex: Human Revolution. It is set after the events in China when Adam Jensen went as stowaway on a ship. The original game blends out for three days and this add-on tells what happened during this time. Jensen finds himself captured on a Belltower ship, ready to be tortured. Fortunately a mysterious hacker frees him and now Jensen needs to uncover the conspiracies of his surroundings.
Despite being set in the middle of the story, the DLC can only be started separately; the main game still skips the DLC content during a regular playthrough. This means the game can't account for the different character builds a player could have used - the add-on works around that by confiscating all equipment and deactivating all of Jensen's augmentations besides the basic setup. The game consists of four differently themed areas of varying size (the biggest matches roughly a typical non-hub area of the original game), which have to be tackled in a linear order, plus a few side quests and a fair share of backtracking towards the end.
The gameplay and level design remains unchanged but attends to one typical complaint towards Deus Ex: Human Revolution: the boss battle takes place in a wide room and allows for non-lethal and stealthy approaches. Also non-player characters more often reference the player's style of play.