I'm thinking about giving this a try in a few months when I have room in my garage and time. I would like to pay someone to do it for me though if the price was reasonable. I can paint it and do the padding, I just need the armor itself made and the helmet. I can do the rest like add detail etc.

Some things may be difficult for me like making a god helmet and boots. I want the boots to have some heft to them so when I walk it sounds like I'm a Spartan. maybe use some rollerblades without the wheels and paint them plus add some pieces to it.

Another idea would be to get some thin sheet metal and cut it to lay over the armor and maybe attaché with rivets and an epoxy then paint over it. Not the entire suite but over some of the flat sections on the chest and arms and legs.

Maybe on the back a small fan running off a tablet sized battery could be used for cooling.

Anyways, some ideas. As for making it a more functional suit. Kevlar paneling might help but to really hold up against impact you would need a composite that's light weight but strong like carbon fiber but even that's heavy and will only take a few blows from a determined attacker.

What makes the Halo suit in the game more plausible is the gel stuff between the body and the armor that locks up and protects the wearer. Its circulates temperature and keeps a seal from the outside atmosphere. Also being huge and full of muscles to help carry that suit is what does it.

So I would focus more on a well detailed and well built suit for show not for use. You can get away with paintball but you will sweat you ars off and probably get it broken after a couple games.