Back 4 Blood players who have played Left 4 Dead in the past will remember that the latter was split into chapters within smaller campaigns. These campaigns were built around themes, and it seems that Back 4 Blood has a similar idea through Acts.
Acts are a slightly more in-depth or convoluted way of splitting up the content in Back 4 Blood, whereas chapters were a simpler version of the same idea. Chapters still exist in Back 4 Blood, but they are a small piece of the overall campaign, which can eventually be played solo or with teammates online.
In Back 4 Blood, Acts are the major pieces of the campaign puzzle that split up the content and the narrative. After Acts, the content is split up into chapters.
Then the content gets chopped into even smaller pieces through various levels that can be played in each chapter. Each one is a small chunk of linear fights that lead into the next area, much like Left 4 Dead in the past.
How long are the Acts and how many are available in Back 4 Blood
Based on everything listed for just one Act in Back 4 Blood, it seems that each one is incredibly long. There are two chapters in just the first act, with each comprising four different levels. This adds up to a total of eight levels in Act one.
However, the entirety of Act one can be completed in a little over an hour on average. Of course, some enthusiasts have already taken on the challenge of completing all eight levels in less than half of that time.
While players are wading through the "Act one" levels of Back 4 Blood in the beta, they are curious about the game's total number of Acts.
With the game officially releasing on October 12, unfortunately, there is no confirmation on the number of acts that players can expect to see two months from now.
Considering that Back 4 Blood is a full price game at $60, it's safe to think there will be at least three Acts for players to get through, or even more. But that is a guess at this point and shouldn't be taken as fact until Turtle Rock Studios releases all of the details.
Hopefully there will be more than a few hours of unique content when the game is officially released.