Here is the full list of all 10 Godsbane Playtest achievements.
Win 1 Match
Win a match without taking any damage
Craft a Unit or Power
End a match with 2 or more Units at 3 stars
Have 5 or more summoned Units alive at any time during a match
Win a match with less than 5 units
Deal 2000 or more damage with a single unit in a round
Save up to 50 mana in a match
Deal 4000 or more damage with a single unit in a round
Win 50 matches