WhiteGekon

you have about 9 creatures with mana ability, or ability to play land from top of your library, but i figured out (the harder way) that this creatures comes to your hand in late game, or they will not survive long enought to give you any advantage. a lot of them will die very quickly and maybe not even survive to your next turn. land search is better in the way, only few players play land destruction spells.
in this deck, i will play at least harrow, kodamas reach and explosive vegetation. maybe coiling oracle and oracle of muldaya.

overbeign of myth will be usable i think :) and you need manaramp.

or change him for Clever Impersonator. you can copy opponents plainswalker, or your own, for double use of your plainswalker :)

kruphix follower is very good with nykthos. mybe i think about change 1 elvish mystic and 1 courser of kruphix for 2 followers. and we (me and my friends) figured out, that 61 card deck is a little bit better. if you have at least 1 player in your group, who play mill. wizards build mills to 60 cards decks and that 1 card more will really help sometimes. so maybe you dont need to remove one of that creatures, or add 3 followers. :)

you play polukranos and vorinclex. how about kruphix, god of horizon. he stores any amount of mana for later use. for example, i played polukranos monstrozity 95 after 3 turns of storing mana. :) maybe mana reflection will help a little too.

another thing is, you can play cards like rapid hybridization for kill enemy minion.

maybe garruks packleader for draw?

i think, you need more manaramp, but nice deck. maybe change astral cornucopia for sol ring. and add hardened scales they will help i think.

maybe Sun Titan, Praetor's Counsel and Maelstrom Nexus? it can help a bit. maybe even Descendants' Path and of course Living Death? :) i like this deck :)

maybe som extort will help. and creature like Crypt Ghast is good enough to help with it :)

http://www.mtgvault.com/whitegekon/decks/animar-soul-of-eldrazi-edh/
if you wanna check it

interesting deck. maybe you wanna play bear umbra and a bit more creatures and more mana ramps. i will clone this deck and create my version of it. :)

i dont know what to remove for mealstrom nexus, and dont wanna play broken kombos. as i dont play ancestral statue in my animar deck :)

Deathbringer Thoctar + anything that gives him deathtouch = kill everything :)

plasm capture maybe?

only one time i played wet dream of riku decks. 25th+ turn = riku + doubling season + parallel lives in game, and inferno titan + rite of eplication on hand. enought mana to copy each and kick rites. :D 2 opponents dead. :D 135dmg only from enter the battlefiel effects :D

nice combo is (experiment cry+)gilder bairn+training grounds+utopia vow = unlimited doubling of +1/+1 counters

another combo "any creature which can untap lands"+freed from real+simic growth chamber = unlimited green mana

and there is plenty more combos going.
another good combo is with kruphix,god of something+doubling cube+geligree sages = unlimited mana :)

i play simics from th times od old ravnica and know almost all of their cards and possible combos. :)

yeah...its sad,that you cant pay aditional 10 mna to 5x copy your time stretch. but i did it once (time stretch was not from my hand :D ). riku is very funny deck, but you must stabilize mana very precisly. and always have lot of mana :D

yesterday game with my crazy riku ended with 27 lands on the battlefield and during my 4th turn created with timestretch(copied and copied) i ended life of my opponents, still 2 turns more to go :) that was crazy sh*t, and that game takes 2,5hours to play.

you can copy one spell and one creature only one time with riku, but there is a lot of posibilities to copy that abillity, or to double tokens.

thanks for some new cards to my crazy riku :)

you can check there if you wish, but this deck is builded just to have fun and f*ck your opponent brains with 924812654 effects/abilities/spells on stack :D
http://www.mtgvault.com/whitegekon/decks/mad-mad-riku/
and i recommend maelstrom wanderer and mindclaw shaman