This is the second main game after Nemesis in the series. Instead on on a one-level spacecraft, Lockdown takes place in a secret multi-level base on Mars. Storywise, the survivors of the first game (which survived the xenomorphs on the spacecraft) are locked away when they arrive on Mars (one of the possible destinations you can have as a goal in the first game), never to be seen again, and are an involuntary part of secret experiments.

Of course, the experiments go wrong, the xenomorphs escape containement, and slaughter the base's scientific and security crew; during this the characters break free and need to escape, or look themselves into the bunker.

So, basically, the game rules and the goals are more or less exactly the same as in Nemesis, only "skinned" differently. But there are also enough differences. You get new game concepts, like power being available on the different levels; different levels, which affect the movement on the board; different xenomorphs with different rules; different characters; …

So far, I have not played this game once, after it arrived from the kickstarter campaign…