Here is the full list of all 15 Slayer Shock achievements.
You finished a Legacy.
You finished Season 4.
You finished a season on episode 7.
You finished Season 3.
You mastered all four skill tracks.
You learned three complete skill tracks.
You finished Season 2.
You learned two complete skill tracks.
You finished Season 1.
You learned one complete skill track.
A slayer is born.
You defended yourself in the Intro.
You completed a stealth mission without being detected.
A Big Bad was dusted by a werewolf.
You finished a season in the last standing neighborhood.