The idea behind the deck is simple. Ramp up and hit a massive genesis wave to overwhelm your opponent. Using primeval titan, it is entirely possible to hit a genesis wave for six on turn 5. Casting the wave for at least six allows Frost Titans, Phyrexian Metamorphs, and Wurmcoil Engine to put the game away.
The biggest weakness to playing gu is that there are few good removal spells and even fewer board wipes. Primary reason that Karn is in the deck is for removal purposes. Anything I cannot lock down with a Frost Titan (or three as the case often is with Metamorphs and genesis waves) is always a target for Karn.
Shrine of Boundless growth wss not in the original version of the deck. It was added later as a two of at first that was meant to make Genesis Waves stupid big. However, as I played more with the deck, I found myself using the shrine more and more to cast titans sooner and use as mana to fuel mana leaks.
The only thing I have definatively decided to keep in the sideboard is autumn's veil. Very, very effective against control. I do have one copy of Thrun main as well.
Glimmerpost. This deck would not be half as good without this card. Primeval Titan paired with this makes me laugh at almost any agrro deck. If for any reason they fail to end the game before I cast a Titan, they are not the ones that end the game.
With this list, I recentyly won an fnm with 38 players. I went undefeated against a gw human deck, ub control, and three versions of wolf run ramp. Skaab ruinator surprisingly was amazing in here. He was a recurring creature from board wipe, and served as an invaluable blocker against inkmoth nexus. The sideboard has been updated to include the cards I actually sided in.
