Here is the full list of all 12 The Stairway 7 - there are Anomaly Hunt Loop Horror Game achievements.
Meet the cute ginger cat
Find your first anomaly
Survive and get to Floor 20
Survive and get to Floor 40
Survive till the red room anomaly
Survive and get to the ending
Survive and get to Floor 60
Survive till you find the rats room
Meet ginger when he is hungry
Meet mister crabcat
Survive till the mannequins anomaly
Be among the few to fully complete survival mode without dying