The idea is my spin on UWr control. It's slow, sure, but it caries main-deck answers to 90% of threats, aggro or combo or control, in the form of copious counters. The goal is to stall your opponent "til they're dead." The deck also features low mulligan costs, and it recovers quickly with its tons of burn & draw. Additionally, the sideboard includes both Thundermaw Hellkite and Keranos; after game 1 one of them should swap out with something non-important or relevant. Keranos giving you either a bomb in a static state, while Hellkite can single handedly turn the deck's focus into combat.
An ideal hand looks like three lands, at least one for each color. Pay attention to life-totals: you'll want to attack your target right when they attempt to stabilize. If neither you are opting to attack immediately, you should announce end-game effects and start dropping creatures. It seems counter-intuitive for a deck like this one to take the offensive, but I think all it needs to reach that level of flexibility is a single hellkite, and changes in play. Judging by what you have seen of their deck, you side in things:
Slow: Keranos, counter-flux, both verdicts, leylines depending on the match
Fast: Hellkite, counter-flux, paths to exile (sans the storm matchup), engineered explosives, leyline of sanctity ,
Either way, you will find yourself with hands full of cards that say flash, and instants.
You have to play these during the oppent's turn, or they become that much less valuable. Wall of Omens is a bit of an odd duck, however it helps stall affinity & RDW for at least a turn. And it's still pretty solid card draw.
If you're playing the slowed down version, don't be afraid of using burn on creatures, because you have inevitability if they don't kill you soon enough. The goal here is to stall until you find Keranos, then let him do the heavy lifting.
In the fast version, you'll want to act as if it's a midrange deck, not pure aggro (it never will be). Bring in counter-flux, board wipes & leylines to slow the game down enough for you to drop bombs and kill them. Engineered explosives is a somewhat unique situation. It could be used in the slower matchup, but you are much more likely to to give her better 2 for 1's in the aggro-deck hypothetical, which is what makes it ideal here.
The deck is very interactive, you will need to get used to waiting on your opponent to make the decision to fumble. Like tennis.