22 lands is abysmally low. You should be looking for something in the 26-27 land range. 28 isn't out of the question by any means.
Chancellor of the Dross isn't a great 2-of. I would only advise playing him as a 4-of and only in metas where you're allowed to take free mulligans (I know that most casual MP groups allow players to take a free one). If you want awesome drain, go with Exsanguinate. Your deck just plains wants 4 of them. They're like ****ing free, they're from a recent set, and they're flat out AMAZING in multiplayer.
Dark Rituals are meh in your deck. You don't have cards like Demonic Tutor, Vampiric Tutor, Yawgmoth's Will, etc. that allow you to make big, explosive end-game plays. Ritualing out a Hippy isn't very scary in multiplayer, it's not worth 2 cards. These should instantly be converted into lands, and even then you'll still want to make room for at least 1-2 more.
As far as good creatures goes, some of my favorites are Dread, Dread Cacodemon, Reiver Demon, Mortivore, Havoc Demon and Helldozer (super underrated card in multiplayer). There's nothing wrong with your creatures I just wanted to give some shoutouts to these kinds of cards :P. Obliterator is a ****ing Moat that also serves as a win condition so I'm glad to see him in here.
There's a guide in my sig that you might want to check out.