That's my current deck. Idea is to have Zombies to recast Gravecrawlers, and using Gravecrawlers and other creatures with Undying to use for sacrificing to use very efficient cards (Disciple of Bolas, Demonlord of Ashmouth, Mutilate). You get nice early aggro from Gravecrawlers/Diregraf Ghoul/Geralf's Messenger, and you get very nice flying midrange with Demonlord of Ashmouth, and Bloodgift Demon (easy to find due to the amount of card drawing in the deck).
Sign in Blood, Bloodgift Demon, Disciple of Bolas, and Liliana of the Dark Realms ensures very good card advantage to keep the engine going. Tragic Slip and Mutilate yields very efficient results due to sacrificing, Gravecrawlers, and Undying creatures. Singleton Zombie Apocalypse with two Mikaeus, the Unhallowed as a situational insurance policy. Liliana of the Dark Realms can also end a stalemate with pump/removal ability, and of course her +1 swamp search gives you enough mana to chain your draw-engine all day long.
Not sure how to make this deck better now (besides getting Cavern of Souls to stop counterspells). Maybe remove 1 Mikaeus, the Unhallowed and add another Zombie Apocalypse because if both Mikaeus are in my graveyard and I cast Zombie Apocalypse, they will just die again (legendary creatures)
even though I'm just trying to use creature control though? I'm not trying to control their hand or anything, I just want to remove their creatures (even if it means sacrificing my own, since I have undying and Gravecrawlers)