Very interesting ambient stuff.
I really like Electro-orchestral Trailer, maybe the most. I think my instinct, even for a background-ish, ambient track might be just to do even more creative experimenting even more with sounds you have. Like in Electro-orchestral trailer, introducing the choir and the strings at certain points were great and very appropriately understated, for evoking mood. I might consider tightening the dynamic range on that track, as that might make it more (appropriately) unobtrusive to a gaming experience.
Very nice. I can see this work complimenting the right kind of game nicely.