The idea of this deck is to discover Mind Blast with Shadow Visions so that up to 4 of them can be used for a One or Two Turn Kill. You will always find a Mind Blast or another Shadow Visions (for Priest of the Feast and Lyra the Sunshard combos because there are so few spells in the deck.

Radiant Elemental and Mirage Caller allow you to cast your 2 cost spells for free.

Alexstrasza and Prophet Velen are all cards that can combo with Mind Blast to easily dispatch your opponent.

Lyra the Sunshard is good for this deck because cheap spells can be played on the same turn that you play her, especially with cost reduction. Also, with double spell reduction, Shadow Visions can fill your hand up infinitely by discovering the other Shadow Visions. This can also work as a Reno Jackson with Priest of the Feast because you can heal to full by constantly discovering your second Shadow Visions.

The rest of the deck is built to enable you to draw your combos.

TL;DR: This deck is a rather consistent OTK with Mind Blast because of the draw power that is in the deck and because of the spell isolation with Shadow Visions. It has the potential to draw endless Priest Spells with Lyra the Sunshard and heal to full with Priest of the Feast. Please post your comments below and upvote for visibility!

EDIT: I added Stubborn Gastropod and Volatile Elemental to make up for the lack of removal. Also, Tol'vir Stoneshaper has been working great because of the added elementals.