This Priest deck is super fun and offers a new take on a typically very control-ish class. As the title suggests, your main threat here is Goblin Bomb that deals 2 damage to an enemy hero. Cards like Whirliglider and Explodinator will help you summon even more bombs, while Mirage Caller and Twilight's Call will help you copy them for even more damage.
As a result, you should have 32 points of damage in the course of a match-up just from the Goblin Bombs alone, which is more than enough to kill any opponent.
And if you're short on the bombs for some reason, then use Leper Gnome and Mind Blast as alternative win conditions.