Scorn

Story related and can’t be missed.

After the incident that unlocks 003, you wake up outside and have to wander around for a bit until you find a way back into the inside of the mysterious building. As you enter, you startle an odd creature that flees into the vents.

Further on you’ll find a skeleton holding a cylindrical key that you take and need to upgrade at puzzle locks elsewhere in the level. You’ll see the critter again while doing this and one encounter unlocks this achievement.

Non-missable story achievement halfway through Act II. When the wall crawling creature entwines with your body during a cut scene.

Video guide on the fastest completion method:

Story Achievement.

For a fast achievements guide check the video below:


Timestamps:

00:00 Intro + 001 Extraction Achievement
06:02 002 Hand in hand Achievement
09:50 003 Hazardous occurrence Achievement
13:53 004 Close encounter Achievement
17:49 005 Key possession
22:43 006 Path Forward constructed
34:29 007 At the lowermost point
39:09 008 Station to station
47:05 009 Detachment
54:59 010 Fluid flowing within
56:11 011 Perception Beyond
56:23 012 Final