Here is the full list of all 18 Succubus With Guns achievements.
Complete a level using only sword or melee
Finish level 2
Find the sword
Finish level 1
Kill 5 enemies with one shot
Destroy slugs on first level
Take training
Kill 100 skeletons by sword
Kill 100 big guys
Die for 15 seconds on start level
Die 10 times on one level
Jump 5 times when the camera is in front of the character
Get killed by slugs at level 1
Finish level 3
Finish level 4
Finish level 5
Finish level 6
Finish game