This is a large-scale game with a lot of pathing options, and the 0.8 pt1 playthrough time depends on many factors. In particular, on which paths in KG you have already completed in season 1 (V 0.7b) and how many separate saves you have for those paths. There are 2(4) main paths, Dom(Good/Evil) and Sub(Good/Evil), but within those paths there are dozens of path variations.
Many serious players have anywhere from 3-4 to more than a few dozen! different saves, distinguished from each other by a set of active flags and variables that affect various events in the game, your relationships with individual characters and even future endings (~14-15 different endings)... The total time to complete the update depends on this.