thank you for the feedback!
in terms of level design, i actually chose a very improvisational style for this demo. i started with a large empty factory, and began filling it up starting from the first room and trying to flow the level around like a maze. i drew all the rooms and layout on paper before i did anything in engine.
essentially, the rooms are all just big cubes. nothing complex. i wanted to have verticality because of the tight space, and i always kept in mind the 2 endings for the game and planned to have space for that.
i use Umodeler in Unity and the models you see are made in that as well as Blender . I use a photo-source workflow you can see on my YouTube.