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The deck looks alright for starters, but I’ll see if I can’t shore it up a little and make it more focused.  I’ll also try to speed it up, since you mention that the deck is too slow for duels.

Now, when it comes to speeding up a deck, there are three good ways to do it.  The first is to increase the amount of cards it can draw, so you need less turns to get the cards you need.  The second is to increase the amount of mana it can produce and the speed at which it can produce it, so you can play out your big threats sooner.  The third is to use cards that cost less mana, or in multicolor decks, don’t need as much of a specific type of mana, so you’re less likely to have cards stuck in your hand and more able to put pressure on your opponent early.
 

As far as drawing cards goes, that’s usually Blue’s territory.  Red is terrible at it.  Green has a few creatures that cantrip, but none of them look right for your deck.  Black can usually get stuff out of the library fairly well.  And for reanimator decks, there’s one great option in Moonlight Bargain.  It does cost five mana, plus 2 life for each card you want to keep, but it would help your deck since it can put cards in the graveyard.  It’s especially good if you can put Borborygmos into your graveyard and Vigor Mortis into your hand.
 

Then there’s accelerating mana, which you’ve already got plenty of in Wild Cantor, Sakura-Tribe Elder, Civic Wayfinder, the Signets, and Farseek.  Frankly, Signets for green-aligned guilds aren’t as good as other Signets simply because Green has so many other ways to accelerate mana.  Wild Cantor gives you a mana while the others give you a land that you can use over and over.  And Farseek can’t get Forests or be Vigor Mortised.  So my advice would be to switch the Cantors and Farseek to three more Tribe Elders, and replace the Signets with two more Wayfinders.  The Tribe Elder especially is great with a Debtors’ Knell, since you can sacrifice it every turn and keep bringing it back if need be.
 

Now, to settle out the colored mana requirements.  Right now one of the biggest problems I see is Scab-Clan Mauler; it’s at its best when you play it early and get the Bloodthirst bonus.  But RG is a tricky casting cost to guarantee in a deck with three colors, and dealing damage first complicates matters.  I’d say replace the two Maulers with two more Golgari Guildmages; they’re much easier to play, are more useful later in the game, help with your recursion theme, and they’re never 1/1.  The other tricky casting  cost I see is that of Rumbling Slum.  Yes, it’s a good creature, and if you really get a lot of mileage out of it, that’s fine, but just try replacing it with Giant Solifuge and see if that doesn’t work any better.  Skarrgan Skybreaker also is a bit tricky with that 4RRG mana cost, and even though it’s completely worth it if you can get it with Bloodthirst, I’d keep an eye out for a better option if I were you.  Gleancrawler comes to mind.

One last thing is your noncreature spells: they seem to be sort of...all over the map.  I’d love to see the Death Denied become another Vigor Mortis, and the Volcanic Hammer become another Putrefy.  The Leyline of Lightning isn’t really essential, and would probably be better off as another Debtors’ Knell, but it is useful nonetheless.  And you don’t have any way of dealing with opposing enchantments.  Definitely try to find room for at least three of either Naturalize or Sundering Vitae.  As for what to drop, well, Savage twister is good, but I don’t think you need three copies, especially with so many smaller creatures.  And Gruul Guildmage isn’t nearly as good as Golgari Guildmage.  I’ll let you make the final decision, though; after all, it’s your deck.

Once Dissension is released this summer, the Red/Black Rakdos guild should provide a whole new arsenal as well.  And if you’re willing to use older cards, the colors you picked match those of Darigaaz the Igniter and all the cards with Darigaaz in their name (especially the Caldera).