You guys are doing FANTASTIC work with this one. Your storytelling is getting better (I hated AoA's plot, liked WiH, loved the gameplay of both), and you did a masterful job of helping me get totally immersed and suspend disbelief.
However, in the first mission briefing, you made blatant reference ("Nothing is true, everything is permitted") to another video game series. Please don't do that again.
I can tell that Assassin's Creed heavily influenced this latest chapter, but actually using THE Assassins' Creed as the creed of the Fedayeen was not a good move. Come up with your own knockoff maxim for the Fedayeen, paraphrase it, alter it, or even remove it -- but your story is strong enough that it can and SHOULD stand on its own just fine without quoting other games verbatim. If you do, the spell of immersion is broken -- I go from being IN the experience, to THINKING ABOUT the experience. Which is a damn shame because you did so good to immerse me otherwise, making reading that all the more jarring.
[EDIT] I stand corrected (see the reply to this An4ximandros posted) re. the origin of this phrase.