The chase begins after you complete the "Make-A-Friend" toy machine. To navigate the vents successfully, follow this specific path provided in community guides :
Vents in Poppy Playtime are frequently used to gate progress or hide secrets. Poppy Playtime FULL VENT CHASE poppy playtime vents
: Speculation suggests the human-to-toy experiments suffered from unending hunger, explaining the 4,000-calorie diet mentioned in factory posters. The chase begins after you complete the "Make-A-Friend"