I can hear Omnisphere and Sytrus clearly all over this, and it sounds great. Atmosphere is fantastic, and you two are working together almost seamlessly here. The only synths that stand out negatively are the choir, as I can hear the harsh, robotic syllables. This, however, did not destroy the atmosphere, which is an achievement in and of itself.
The transition around 4:30 is fabulously implemented, although I feel it was a bit of an abrupt conclusion to such a spacious composition, much like the staccato strings in the lower register also seem somewhat abrupt. I believe that adds to the theme of dangers existing outside the biodome, however. You both did a very good job of conveying theme.
I wish I had more to say about this piece technically than praise, however, praise is well deserved, even with the few technical flaws here. Very nice work, the two of you, and thanks to Step for pointing me toward this piece!