Colorless deck.

Why not run the Urza lands?

Happy to help

Actually I think having Deserted Temple and Eldrazi Temple is better than having those lands you mentioned.

I didn't notice it was legendary. Fixed it.

That land combo is nice, but it will seldom deploy effectively. There's about a 5% chance you'll get the cards to produce 4 mana from 3 lands in turn 3, which means you are practically assured deploying on the same mana curve as everyone else. Still, 5% chance of a better mana curve is nothing to be sneezed at when many two or three color decks may stall for a turn.

I think the creatures are the major problem. The zero mana creatures are nice...but you don't have any turn one instants or sorceries, so if you don't draw a land on the first turn and can play a mana creature, you should mulligan. I don't see a reason for having them when your deck would operate just as well with a mana creature.

I'd recommend replacing them with arcbound creatures, like Arcbound Worker or Arcbound Stinger. The nice thing about arcbound creatures is that you don't really need a bomb. You can put one in there to keep the mana curve smooth, but so long as one is always on the field their +1/+1 counters pass from one to another until you can turn a grunt into a bomb.

Also that Leveler has got to go. You exile your library to summon it, so the next turn you'll not be able to draw a card on your draw phase and lose automatically. It won't have even recovered from summoning sickness. I can see the card working with some decks if it's combined with something like an Elixir of Immortality: if you know that the stuff left in your library is useless for the rest of the game, summoning Leveler and using the Elixir in one turn will drastically trim down your library while putting a great monster in play.

But in this deck it's just suicide. I don't even see how you can use it without killing yourself.

Huh. I was not aware of that combination. Point taken. Are you sure that an elixir wouldn't turn the graveyard into a replacement library?

That combo changes things. I expect it's vulnerable to control decks: The chances that this will coalesce in the first few turns is reasonable, but small, but if your opponent has cards like Unsummon, Broken Dam, or worse, a "creature doesn't untap" instant, sorcery, or planeswalker, you're deck won't deploy right.

Let's assume you get the cards to cast a Phyrexian: the earliest your deck can deploy it is in turn 3, so a good player would wait until you attack with it before unsummoning it. It's now turn 5, you may be able to play two of your beasties for a total of three, but at this point the opponent can deploy something like Tamiyo, the Moon Sage.

Long story short: beware control decks.