Buy Steel Battalion Heavy Armor from any old retailer, and you'll get to play the game. Buy it from e-Capcom, and you'll get to play it while cosplaying!
The Steel Battalion Heavy Armor Limited Edition includes a copy of the game, a soundtrack, an art book, a jacket (available in selectable sizes), a leg bag, and a helmet (it's actually just a cap, but it certainly looks like a helmet!).
Obviously, you're going to have to pay just a bit extra for this special version of the game. Pricing is set at ¥35,000. The game on its own costs ¥7,990. A set bundling the game and soundtrack costs ¥8,990.
The Limited Edition and soundtrack version are e-Capcom exclusive.