Here is an Armenian Orthodox Badarak celebrated by H.E. Archbishop Moushegh Mardirossian, for comparison:
Other than the use of the organ in the opening hymn and some of the externals, it's pretty far from anything Roman. Armenian Christianity is interesting because it is so old that it has gone through distinct phases of outside influence, so you can spot a lot of different influences if you are attuned to them. The organ and some of the vestments probably remind Roman Catholics of their church, but the actual chant form (even with the organ) is, from an OO perspective, basically what you'd expect if you mixed Syriac chant (the Armenians originally worshiped in Syriac before the time of St. Mesrob) and Byzantine chant -- completely understandable when you consider their cultural and geographic ties between the Byzantine empire and the Persian. Check out the unaccompanied chant at ~18 minutes in the above video -- sublime, but really, really not Latin.
(Not that there's anything wrong with Latin chant, of course, but just pointing out that the differences between and actual Armenian liturgy and what you have in the video of Pope Francis are pretty striking, once you orient yourself to the Armenian way of doing things.)
My question would be: Why is there a Roman mass being served for Armenians? Is it connected to remembering the genocide or something? I don't know enough about the relations between Rome and the Catholic Armenians to know the context of this (I've never met an Armenian Catholic, only Orthodox). Anyway, I guess it's kind of neat to see...just confusing, from a ritualistic perspective.