Updates
Completely fixed the issue in Chapter 5 where Whisper could disappear near the edges of the map. Even if it gets stuck or vanishes, it will now always return properly.
After retreating in Chapter 5, Whisper can now reappear not only from behind you (left or right), but also directly in front of you. You'll need to watch all directions.
Fixed an issue with the newest achievement that required completing all three playthroughs in a single game session. Progress is now saved, so even if you quit and return later, completing the game three times in total will unlock the achievement.