Depending on how much you explore, and whether you prefer a full frontal assault or a more stealthy approach, Mothership Zeta will last around three to six hours. It doesn't have the big, open areas and side quests of Point Lookout, or the added benefits of Broken Steel (such as the increased level cap and story extension), but this DLC is still a fun adventure that will net you some cool-looking and powerful energy weapons when you're done. Overall, Mothership Zeta takes the basic game design of Operation Anchorage and fixes many of its problems, giving the player a longer experience, with more interesting environments, enemies, and equipment, and several different and interesting small gameplay elements to break up the monotony. If you enjoyed the previous DLC, you'll probably enjoy this one as well, and the cheesy sci-fi themes will probably win over some new fans as well. One word of caution, however - if you don't already own Fallout 3, you may want to wait a couple more months for the Game of the Year Edition, which includes all five DLC for free.