Turn 4 Emrakul, the Promised End orTurn 4 Ulamog, the Ceaseless Hunger? Exile their lands!
This deck is totally built around Aetherworks Marvel and how to break it.
The end goal: have 6 energy and cast Aetherworks Marvel on turn 4 for an immediate activation.
There are many ways to get to 6 energy by turn 4, so this deck is not narrow. In fact, many of the cards on here help scry or look at the top of your library so that you can get to the Aetherworks Marvel you need, or you can scry an Ulamog, the Ceaseless Hunger so that you can ensure it stays on top for when you activate the Marvel.
Example: Turn 1: Island, Thriving Turtle = 2 Energy.
Turn 2: Aether Hub, Glint-Nest Crane = 3 Energy. Find an Aetherworks Marvel.
Turn 3: Any land, Woodweaver's Puzzleknot = 6 Energy.
Turn 4: Aetherworks Marvel, activate it and KABOOM!
Like I said, there are many other routes to 6 energy by turn 4.
Thriving Turtle: one mana, 2 energy, and a blocker
Glint-Neck Crane: 1U for a 1/3 flying blocker that lets you look at the top 4 of your library and put an artifact in your hand.
Aether Hub: a land comes down with 1 Energy
Attune with Aether: Find the other land color you need (not that this is a complicated mana base) and get 2 Energy. Nice one drop.
Glassblower's Puzzleknot: 2 Energy and scry 2. On turn three, crack it and do it again.
Woodweaver's Puzzleknot: Gain life? Sure. 3 Energy on turn 2? Awesome. Repeat it on turn 3 and this fuels the marvel on its own!
I also added in the newly spoiled Aethersquall Ancient. If you hit it with the first activation, it can fuel another activation very quickly. Especially if, on turn 5, you throw out or crack a Woodweaver's Puzzleknot. That's turn 4 and turn 5 activations! Ouch.
Am I missing something here, or is this broken? If you really want to go the distance, you can use Cryptolith Rite for a potential Turn 3 activation using Turtle energy.
If it's not working out, Metalwork Colossus could find a home here.