On my iPad, I defeated one level of Gideon with Jace, Day’s Undoing, Talent of the Telepath, Turn to Frog, and a bunch of bounce spells. But I don’t have the exact deck list.
With the new ability to discard, it makes sense to run as much removal as possible and pitch it when it’s not needed. There are only 4 creatures in this deck, and they all have some ability to affect the game state. 3 of them do damage directly to creatures. Embermaw Hellion also adds additional damage. Volcanic Rambler wipes out gems, sometimes destroying enemy supports or gaining mana / loyalty counters in the process.
I will note that a functional change has been made to Chandra’s Fury. It will not work unless the opponent has at least 1 creature on board. Previously, you could fire it off to do 4 damage to the opponent, even with an empty board.
It isn’t the best spell, but it can sometimes come in handy, and I don’t have any other removal at this time.
Here is a Jace build which beat several challenges:
Anchor to the Aether
Artificer’s Epiphany
Claustrophobia
Day’s Undoing
Disperse
Displacement Wave
Scrapskin Drake
Separtist Voidmage
Talent of the Telepath
Turn to Frog