Full list of all 13 Tentacle Girl achievements. It takes around 0-1 hour to unlock all of the achievements in the base game on Windows.
The base game contains 12 achievements, and there is 1 DLC pack containing 1 achievements.
Complete level 11
Complete level 12
Complete level 6
Complete level 7
Complete level 8
Complete level 9
Complete level 10
Complete level 5
Complete level 4
Complete level 1
Complete level 2
Complete level 3
Install DLC