Speed Spell Burn Deck MTG?

Even though it is a 40 card deck you will want more mana in it. Likely you will draw hands where you will have to mulligan which reduces the amount of damage you'll do in your 2-3 turns. Assuming the opponent isn't countering or preventing the damage. Plus you might need to remove some of their creatures or a planeswalker.

Once you empty your hand of spells you're relying on your draw cards. At that point if the opponent isn't dead you probably are.