Here is the full list of all 11 HordeCore Prologue achievements.
Cook something.
Play Horde Tactics.
Walk in Sneak mode.
Craft an item.
Make a dialog decision.
Equip a new item.
Play the Prologue.
Lost a match of Horde Tactics versus Gramps.
Complete the Prologue.
Survive The Gauntlet.
Destroy a Mercenary Wagon.