The look is simple, but that's if that's what you trying to do then it's OK. It looks kind of like some kind of military trying simulator. I still think you maybe could make it a little more open (possibly take out the pillars on the top level), and it wouldn't hurt to maybe add another color for accent so it doesn't look as much like a grey blob.
Creativity/Style: 5/10
Execution: 9/10