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