Having taken courses in veil landscape painting (which isn't digital as you done it, but the concepts are the same), you'll want to flatten and straighten out the layers that head off into the linear perspective horizon. (You can still have cliffs on the first layer (the furthest one), but the bumps need to be a lot smoother as the human eye cannot perceive detail at that distance)
That layer also needs to be brought down a bit. You can tell it is awkward by the steep incline your power polls and its associated connectors need to take between layers 1 and 2.
Otherwise, it looks great. Love the TF2 symbol sun. Good show, sir!