>Begone Long Description<
Let's start with the core of the deck: Polymorph and Proteus Staff, splitting it up 4/2 because of Abrupt Decay and artifact hate. The ideal behind these cards is very simple, and it means that I must not play any other creatures besides the Emrakul I'm morphing up. Having 6 of them means that I don't have to waste space for tutors or draw spells solely for being draw spells, which is a good thing, as tutors would really destroy my game 1 plan.
Following it up are the token generators. Bitterblossom takes center stage as being an excellent turn 2 play, while also being a pretty decent control win con in and of itself. While it takes about 5 turns for it to turn into a major threat, propping it down turn 2 and proceeding to control the rest of the game isn't that bad of an ideal. The biggest benefit of it however is that as long as I can get this down on turn 2, I can play any of my 6 morphing cards to get an Emrakul on turn 4.
Timely Reinforcements comes up as the 2nd token generator and it is mainboarded because of the prevalence of aggro and RDW. Gaining six life and generating tokens to block for a couple of turns is awesome in being able to make sure I can control the board long enough to win via Emrakul.
Creeping Tar Pit, Shambling Vent and 2 Blinkmoth Nexuses are here because manlands are excellent methods of generating Polymorph targets in the late game. I've split them up in such a way because of A) having creatures to morph for mid game in Blinkmoth Nexus and late game in Creeping Tar Pit and Shambling Vent makes me versatile at all points of the game. I can use Blinkmoth because my mana base is nonrestrictive, only 5 cards have double mana in their cost, and sideboarding against certain archetypes makes this even easier. Creeping Tar Pit is wonderful against opposing Lilies, and Shambling Vent really holds its own against RDW and Jund.
Liliana of the Veil is here because A) she generates the oh-so-lovely Lili-hole, which is a state of condition that you force onto your opponent in which they can't do anything. They either discard what's in their hand or get it sacrificed. And B) because she is an excellent method in being able to get rid of Emrakul. Emrakul then becomes a shuffler, refreshing your library with a bunch of new spells. This is a lot more beneficial than it may seem, because what this basically does is it resets your deck count to a pre-game state with less lands, meaning that you have a better chance to draw value than to draw junk. Oh, and she is also the primary reason why I can have 6 morphers, because I can discard extra ones to her.
Finally, we have Gideon, Ally of Zendikar. Bit of a surprise, this one, coming from BFZ. He holds plenty of value in control decks, and even more value in this one. He can either protect himself by generating a 2/2 token each turn, or he can be a win con and swing as a 5/5 indestructible. Being a token generator makes him excellent with my morphers, but he himself can be morphed with Proteus Staff, as the staff doesn't care about indestructible (Polymorph, however, does, which makes this situation quite fringe). Important to note that he must always play that 2/2 token the turn he comes down.
The rest are all pretty self-explanatory. The removal must all be cheap in order to deal with combo like Twin and Bloom Titan, while the counterspells also need to be cheap as the only thing they are really doing is countering counterspells or removal spells. And finally, the discard hits combo and control decks nicely, or it becomes Lili fodder.