I'm curious to ask how many layers this was and if everything was sketched out first as one piece or done separately in each layer. Like if the people were a separate drawing/layer, shadows separate or if everything was drawn in one sketch and than went from there. This looks really technical/complicated but nonetheless amazing.
Everything was sketched out and designed before hand. It was around 80 layers of stuff. I created plenty of masks/shapes in a different file- of various things like floor vents, panels, ceiling graphics etc. I used those masks and placed them in perspective with the transform tool. I then painted within them using clipping masks. The people were added in the end.
I did several thumbnail sketches of how the lighting would work, planning ahead is key. I had several variations on that. The colors are borrowed from the game.
Sorry I didn't get back to you right away, let me know if you have any other questions!