Alrighty. This deck is casual multiplayer heavy, and it obviously shows. It's not necessarily designed to win, but to disrupt as everyone else at the table if it's ignored.
The concept of the deck is to ramp up into making a large amount of saproling tokens, which can then be sacrificed to do a large number of things. Those things include causing opponents to take damage and/or lose life, sacrifice creatures, give yourself a lot of mana, resurrect creatures in the graveyard, boost the P/T of other saprolings for a swarm style attack, draw cards...
This is more of a synergy deck than a combo deck. Various pieces have multiple purposes for existing in the deck. The more pieces you have hit the table, the closer you are to getting something nasty to go off.
Various synergies include:
Earthcraft & Squirrel Nest - A classic. tap a land to get a squirrel. tap a squirrel to untap the land. Repeat until you reach the desired number of squirrels. Altar of Dementia or Altar of the Brood act as a win condition.
Nemeta, Ashnod's Altar and Earthcraft, Oh My - Similar to the above combo, but involves sacrificing to get the mana to use Nemata's ability to make saprolings. Zulaport Cutthroat, Slimefoot & Altar of the Brood are the win conditions to this one.
Let's Clear House! - Either of the above combos with Grave Pact out and you force opponents to sacrifice every creature they have. Great way to control creature presence until you get a win condtion on the field.
Paint it Black - Painter's Servant. It's banned, I know I know. But I don't abuse it. Much. Make everything in play Black in addition to their regular colours and suddenly Savra goes from typically netting you life when a saproling dies to a second Grave Pact.
Overrun! - Garruk's ultimate with an army out. Those 1/1 chumps suddenly look a whole lot scarier. 'Nuff said.
Verdeloth and the Circle of Life - This one is a bit more involved. If you can get stuff like Earthcraft, Golgari Guildmage/Malevolent Awakening & Ashnod's Altar/Phyrexian Alter. tap everything thing you have to get as much mana as possible. Sac what you can (other Saprolings) to get even more. Cast Verdeloth with a huge kicker. Sac him to whatever sac outlet you have. Use the Guildmage or Malevolent Awakening to get him back to hand. Tap the tokens you now have to untap your lands, tap your lands to put mana in your mana pool. Sac tokens to the Altars to get even more mana than before. Cast Verdeloth with a huge kicker. Pairs up well with any of other win conditions.
Slimefoot and the Ritual Sacrifice - What happens when you Get Slimefoot, Heartbeat of Spring, Earthcraft, & Ashnod's Altar together? Sacrifices to help the land prosper as much as you want. That and draining opponents of all Life to feed your Life, one point at a time. Mufasa would be so proud.
The deck is pretty resilient since many of the cards are used in multiple strategies, so opponents wrecking your stuff never quite wreck what you're capable of doing at any given time. It's a nice fun deck just to cause sheer havoc.
The question might be: Why Garruk, Cursed Huntsman? Why not any other G/B Planeswalker? The wolves are a definite reason. They're great fodder for the sac engines. His -3 is nice too. And his ultimate just plain fits well with the token generation. Garruk Relentless fits due to the wolf tokens as well as his second ability when transformed. Gotta love tutor effects in a deck that gets value from its creatures.
Any suggestions or constructive criticism is definitely welcome! I'm always looking for ways to tune a deck to perform better!