Here's a general shot of the Halo 3 Marine costume I finished putting together.
Done using a method with pepakura. Mainly consists of papercrafting the armor and then layering it over with fiberglass resin and cloth.
Used ABU jacket and pants for uniform, "drop-leg" rigs on the thighs.
All held together with some velcro and duct tape. May need to improve that soon, parts were coming apart in the short time to take the photos.
M4 airsoft rifle used until I get a Halo-appropriate weapon to replace it.
All in all, I think I'm satisfied with how it turned out. Hundreds of mistakes were made, and I intend to avoid those mistakes in the future. However, this was a first-time project and I learned a lot. I've refined some methods and I'll try a different style next time around.