Death's Door: main story about 9 hours; story with some extras about 12.2 hours; 100% completion about 16 hours. These are IGDB player-submitted averages from 6 submissions, not a deadline or a prediction of your pace.
Source: IGDB player submissions
Community playtime data is not available for Death's Door yet.
Game Tales keeps what happened between you and a game in one Tale you can keep building.