Very nice concept sheet. I love the variation of mecha on the right. The names for each part are very helpful. It would be nice if you had typed them to play along with the mecha theme. Plus, its just easier to read.
You did a great job with the geometric form of the mecha as well as the shading. These are really detailed and intricate.
Maybe this concept could look a little more professional with the title. The layout is fine and really interesting. Maybe you should give a name for each mech and have the title above them instead of numbers.