From scientists who did work that could unravel what is causing the zombie outbreak to individuals important to the relief efforts, your entire gameplay basically centers around escort quests. They are civilians who will fight to survive just like before, but you can't play as them - you just take them back to your base and defend them until they can be extracted.

This ties into the overarching narrative of a military unit staying back in the city proper to save very important civillians, as that's exactly what you're doing. Whereas the 'high-value' NPCs to save in Breakdown are a natural sort of high-value because they offer you a generally-speaking much higher-level survivor that you can then subsequently play as, in Lifeline those 'high-value' survivors are all NPCs. The ideas of having to rescue valuable survivors, for example, is front and center in Lifeline, though not as valuable to the player in this iteration. In retrospect, Breakdown feels like a sort of prototype for Lifeline, a genesis for a lot of the general progression ideas which were then further expanded in Lifeline. Lifeline builds much better on State of Decay than its predecessor Lifeline, while it has its own problems, certainly does breath some more life into the game, with much more to offer to the game experience than its predecessor Breakdown, which we reviewed here. You can read our original review of the base game here. It is not stand-alone and requires State of Decay to play. State of Decay: Lifeline is the second DLC for State of Decay by Undead Labs and produced by Microsoft Games.

State of decay lifeline and breakdown