I was looking at trying that list too, it seems like someone finally found a decent shell for Mercurial Pretender. I think I would want Pharika's Chosen in there, though, and would personally cut both Suffers and both Ragers. I haven't played it yet, though, so I could be wrong.
I think I would also cut one Rescue from the Underworld for the second Rune-Scarred Demon. You have Undying Evil to blank some removal, so Rescue feels like a late-game bullet rather than a core card and the Demons let you tutor it if necessary.
He made an addendum that has 4 Pharika's Chosen in it (cuts the Ragers and Inspiration). I don't know if Suffer the Past is necessary or not given I've only played 4 games, but I went 4-0 and I won one of the four because I cast Suffer the Past when my opponent swung in for lethal, which meant I survived and killed a couple of creatures that prevented a second lethal swing.
That particular game was an amazing game where my opponent blanked Shadowborn Demon and Dinrova Horror by casting
God's Willing FOUR times during the match. I only ended up winning by casting
Mercurial Pretender on Shadowborn Demon, returning it, then casting again several times. Probably in a normal match Suffer the Past isn't necessary, but I don't know.