Very cool world!
Really enjoyed reading all of the dialogue from the robots, and I liked how the welding gun pushed you back as you shot so you could kind of use it to "fast" travel. Would have liked to see the different noble gas shaders/filters to be used in the gameplay or world, perhaps having different districts utilize different gases, as I found myself sticking to one of them (Krypton, baby!). And I noticed the slight lag on mouse movement, which didn't hurt the gameplay. Just pointing it out, as I could very easily tell since I normally play alot of fps games, and Im sure most people have.
Overall, I enjoyed exploring the world, and its quite impressive seeing 3D games being made with gamemaker!