Might be OP in a Turtle shield + Eternity (maybe flying) stall.
30 (usual opponents deck) - 16 (Blitz) = 14.
14 turns to do 100 damage.
SoG + Eternity + Turtle Shield can easily stall for 14 turns .
Only testing will tell but nice card.
I am seeing four miscalculations/mistakes in there:
First, the opponents deck has usually 30 cards, but he draws 7-8 of those in the first turn. In the worst case, there'll be 22 cards left in his deck.
Second, 6 times 2 is 12, not 16. So so it'll be 22-12 = 10.
Third, you're missing the initial turn in which no cards are drawn, so the enemy has 11 turns to deal 100 damage.
Fourth, if you try to delay the enemy by using Eternity or Reverse Time,
the opponent will not progress through his deck. Based on the same mechanism how player use eternity to avoid deck-out.