I was so proud especially of the BG team on this game. You guys rock! I always try to work with the ideal artists for the job, especially on a license like this where it's critical to nail the style of the source material. I'd worked with Sven and Vedsten previously, but had only been a long admirer of Helm's style. The harsh, dark tones of his artwork seemed perfect for this project. I auditioned Helm and another (well-established but will-remain-unnamed) pixel artist at the same time, and Helm blew the other guy out of the water. Hopefully he doesn't mind me posting, but this was Helm's audition piece (sprites and HUD added later):

The instant I saw that, I knew we had our game's style. That image captured everything I love about James Cameron's aesthetics from the film, and what's more, it was a very dark and complicated environment, perfect for creating fear in the player and giving the aliens areas to hide.
Helm worked tirelessly to create the bulk of the Sulaco ship (which is massive and incredibly varied). Ptoing and Vedsten helped with a few areas of the Sulcao toward the end of art production. Vedsten collabed with Helm for LV-426, and handled all the organic xeno sections. His alien hives and derelict ship interior are just gorgeous.

Ptoing owned the Phobos facility, which has a ton of great details and easter eggs scattered throughout (all from Ptoing's brain). Jawsh also helped with BGs in a few areas, but primarily designed all the game's amazing sprite models.
Last thing worth mentioning - these guys didn't just act as artists, they constructed each world from start to finish. What you see in the game comes 100% from them. We didn't use tilesets on this game. Instead, I gave these guys limitations on tile count and color palettes, and then very simplified 1:1 floor layouts, and they pixeled everything over those layouts in multiple layers. I've taken that approach on a few games and while it can be an intense, draining process, I find it always yields the best results because the artists are in control of where they put their detail, and how the spend their tile budgets (as opposed to having a level designer work from a very limited tileset).
Anywho, congrats again guys! Some of the best pixel art in any WF game ever created, hands down.