The Yushkov Experiment [Master Gauntlet Cleared!]

--If you are looking for this deck's less greedy twin, please check out Yet Another Yushkov Experiment [Master Gauntlet Cleared!]!--

This has been the funnest deck I have built so far around our newest promo, Yushkov, the Usurper! It has yet to pass the 6th round in a master gauntlet [seeEDIT], but barring some unlucky draws I think it has the wheels to cross the finish line.
The basic idea is to draw your Initiate of the Sands, turn 2 Ripknife Assassin into your Magus of Celerity, then pull off Vara, Vengeance-Seeker for stability or Crimson Firemaw to start cheating out the big guns, typically the 3F in Yushkov, the Usurper's cost relegates him to turn five, but it pretty much guarantees you will have the power the following turn to drop any of the bigger bombs on the board to wrap the game up.

EDIT 1: I have beaten the Master Gauntlet with this list a couple of times now!

-and-

In retrospect I think the market could use some tweaking as I usually pick Azindel, Revealed, Memento Mori or Passage of Eons[/cards].
Thundering Kerasaur was intended to help from behind in regaining hand advantage as this deck plays fewer spells and an 8/8 for 6 seemed like solid tempo, and Ancient Terrazon was intended to be an answer to boards with single threats or provide guaranteed 8 damage swings. However, typically neither of these situations present themselves where the Kerasaur or the Terrazon make more sense than silencing the opponents board or dropping Azindel to start stealing cheap cards off the top of the opponents' deck for hand advantage.
Any thoughts on some alternatives for the market would be greatly appreicated, otherwise please give this list a try and have a blast!

EDIT 2: After some helpful tips from Twitch chat, I substituted in Worldbearer Behemoth and Sandstorm Scarf for the Kerasaur and Terrazon in the Market. I also switched out In Cold Bloodx2 and Deathstrikex2 for Annihilatex4.
Thus far, the Market changes have been much better alternatives and curve the Behemoth out nicely. The kill spells swapping out thus far seems to be a bit of a wash. The mono-color restriction has worked against the swap a few times, but the cheaper cost has certainly played a role a couple times, too. Perhaps a happy medium between the three will work, but as of writing this I have not tried splitting them, will probably try 2x Annihilate, 1 ICB, and 1 Deathstrike to see if that has legs (although, I am not a fan of 1-ofs outside the Market).
It was also mentioned that the Shadowlands Feaster was possibly not the strongest choice, but my intention was to lock the opponents void down between the Feasters and Jekk, Lone Gun. I tried a few runs without the Feaster by swapping in a pair of Steward of the Past and was not satisfied because it also revealed a weakness to fliers when the Stewards would show up, but the Crimson Firemaws decided they wanted to stay in the deck.