I just finished my first 1-100 floors solo and didn't get it. Instead it rewarded me with Pal-less palace I. I decided to start all over on another save file and do 1-100 again and still did not get it. I heard you can die on floor 101 to get the achievement but I really don't want to waste my save file since I plan on trying to get to floor 200.
Proof https://imgur.com/GXIPfXE