Stacked is my favorite, mostly because of its open spaces, felt easier to navigate, great lighting and item placement.
Icarus feels like some kind of futuristic urban environment, like on some sci-fi movies.
DmOutrage looks very good, sylish.
Catchment looked like the most realistic one.
I enjoyed playing all of them. Icarus, DmOutrage and Catchment felt more tight, and loved the vertical playing in Icarus, grenades and rockets falling from everywhere.
You all guys did great , thank you very much.