Here is the full list of all 17 Monster Gals achievements.
Completed level 1.
Completed level 2.
Completed level 3.
Completed level 4.
Completed level 5.
Completed level 6.
Completed level 7.
Completed level 8.
Completed level 9.
Completed level 10.
Completed level 11.
Completed level 12.
Completed level 13.
Completed level 14.
Completed level 15.
Completed level 16.
Complete all the levels.