This concept is very well designed and planned. The humaniods portrayed give a feel of strength, finess, and authority. The armor has a very futuristic feel, and the title of the work gives a good background and thesis for the characters. The design follows well in each portrayal, and the colors and forms are quite intriguing.
I also like how each character seems to be some version of the first, as if they are of different rank or status than each other. The lines and shading are well done, and the persons have well-proportioned features. There also seems to be a bionic or robotic feel to these suits (I'm guessing that they are suits, and not actually full-out robots, given the features and humanoid stancing).
The color scheme works well, and the world glimpsed here is very interesting. I would love to see more of these "policemen" and other peoples from their world set. These characters portray more than just a design, they show a small piece of their own hidden universe.
Just loved how you put a lot of thought in this. The designs are great and I know you put a lot of work into this. Although putting details in the picture would be nice. Like rust or something but this is still a great design. Also, I suggest that you should sketch it out even more and add further and awesome features onto the design but still this IS THE MOST COOLEST DESIGN EVER! AGAIN THE MOST COOLEST DESIGN EVER! They also look like they came from the Hunger Games... But you should do a series about this right?
I love the ideas and concepts to your work. They invoke a lot of promising thoughts, and each piece you create shows off it's own little world. I would love to see a lot of your characters come even more alive, and see more of their universe.