What? A modern deck with only 12 creatures? There are half as many Planeswalkers! It's okay because the deck synergy is amazing. If you've ever gotten frustrated because every time you attempt to make a play, your plan was thrawted by your opponents control, this deck will let you pay them back. It does just what the USA loves to do. Control EVERYTHING!
The deck is never meant to be top decking. But the creatures aren't a huge part of the deck until mid to late game. Don't worry about playing good spells early because you'll be flashbacking them later.
The spells are pretty much totally meant to control the field, with the exception of the two different types of charms and the Cloudshifts. The cloudshifts are to flicker your Snapcaster Mages to allow for another flashback swing. The same goes for the Restoration Angels, never mind being a big scary 4/4 flyer.
All of the lands with the exception of Celestial Colonnade might hit you, and most will, but life isn't a problem. The Boros Reckoners are some big fixers of the deck. Comboing with these are the main use of the Charms.
The Boros charm is used in two different combos, one resulting in infinite (if they don't scoop you have to choose a finite number) life, and a swing of infinite damage directly to an opponent. The first combo requires a Boros Reckoner in play, and a way to cast both a Boros Charm, and an Azorius Charm. This can be done with either flashback or from hand. The second combo replaces the Azorius Charm with a Furnace of Rath in play. The tricky part is making sure The Boros Reckoner is going to take damage as soon as one of the combos begin. I recommend swinging and waiting until blockers are declared, but in a pinch, two of the Planewalkers and The Lighting Helix all can throw 3 damage at something. (Any amount of damage to the Boros Reckoner will work for these combos)
The way the combos work: Remember both of the combos REQUIRE the Boros Reckoner to take damage AND the ability to play a Boros Charm. The Boros Charm can grant Indestructibility to your creatures until end of turn. While The Reckoner is Indestructible, damage will not kill him. This allows him to take the damage dealt to him, and target himself, dealing more damage to himself and making a loop that lasts until you choose a new target. For explaining both specific combos, we are going to assume that The Reckoner is taking 3 damage. (because that's what we're able to hit him for)
Combo 1: After the damage is coming to The Reckoner, we will make him Indestructible, (explained above) and then use the Azorius Charm to give him Linklink. Because Lifelink gains life on damage dealt and isn't specific to combat damage, The Reckoner’s damage loop now gains us 3 life per run. (Amount of damage explained above) Since the loop runs until a different target is chosen, we now essentially have infinite life, or the biggest number we can think of.
Combo 2: Once again after damage is coming towards The Reckoner, we will make him indestructible, (explained above) but this time, we will have had to set up this combo a little bit more than only having a Boros Reckoner waiting to be hit. This Combo requires also preliminarily playing a Furnace of Rath. The Furnace doubles any damage taken by any player or permanent, so in this case, instead of 3 damage coming at The Reckoner, he has 6 coming at him. (amount of damage explained above) Now back to making him indestructible. He can now take his 6 damage hit and had 6 damage to dish out to something. Again he will begin his loop of targeting himself. He then takes 12 damage, then 24, then 48, and so on and so forth. The damage will keep doubling until a new target is found. At which point that the damage dealt is going to be higher than the other players life total could be, (make it a decent amount higher than their current life total in case of last minute life gain spells) throw it at them.
Don't worry about artifacts or enchantments that will affect the way these combos work, because the deck has cyclonic rifts to temporarily get rid of those. Wrath of God will also fix the board state in a fix, and won't hurt us much as long as you don't have all 12 creatures out. Even if that is a problem, find a way to add a Boros Charm onto the stack. Remember, the deck has a very high instant and sorcery flashback rate. If at all possible, don't let your graveyard get exiled. There are dissolves for countering those oh crap spells. Save them in hand until you have a way to flashback them or if something very, very, scary is played. But if it's going onto the board, and can be targeted, it shouldn't be a problem. If not, hold out for a Cyclonic Rift or a Wrath of God.
Often forgotten tips of the deck:
1. Celestial Colonnade has vigilance, so if you're really hoping to use a path to exile on one of their creatures next turn, but only have 6 mana, hit 4 damage with the Colonnade and tap it for mana later.
2. After a creature gets Cloudshifted, it comes back untapped. This allows for unexpected blockers. If you're hoping for a spell from grave and need a bigger blocker than Snapcaster Mage, you might consider Cloudshifting your Restoration Angel instead and using her ability to flicker the Snapcaster Mage to get both a 4/4 blocker and a spell flashbacked.
3. Boros Reckoner doesn't have to be dealt damage by an opponent for begin the combos. You can do it yourself with Lightning Helix, Ajani Vengeant, or Ral Zarek.