Thebeeja

I considered it, but i found it too expensive manawise

Gotta say, didn't expect people to take the deck this seriously... i mainly just had a fun idea with black mana ramp for casual play, and well i don't expect to use it for tournaments... i'll use my innistrad zombie deck and creature flashback deck for that.

First of all, you got too much of everything. Chance is you rarely will get yer combo in play. I'd reccomend you to get Rooftop storm ("You may pay 0 rather than pay the mana cost for Zombie creature spells you cast." for 1 island and 5 noncolor mana) and get rid of anything unrelated to zombies or graveyards
If you want you can look at my blue/black zombie deck http://www.mtgvault.com/thebeeja/decks/innistrad-block-zombie-deck/ if you need inspiration... Works quite well.

If you're planning to go with the worldfire, how are you planning to finish the opponent off? if he manages to get 1 mana and 1 burn spell, you've lost even though you managed to get up to 9 mana for the worldfire. A suggestion could be to oblivion ring one of your creatures you don't plunge, and as worldfire exiles everything, the creature gets back in as O-ring becomes exiled, being able to finish it off before the opponents second turn.
I do like your idea of using creatures in red to get mana, tho, mainly as i use it myself, tho not in standard :p