Not all music can survive the a capella treatment, let alone the "Geekapella" treatment. Goofy dudes (Max and Sam) singing geeky music, sort of in tune and sort of out of tune… a lesser theme song might lose some of its dramatic heft. Not Metal Gear Solid.
No, when the heroic theme entered at 2:22, my first thought was, "Wow, even in this goofy version, the MGS theme kicks fucking arse."
That version was pretty fun, but let's go ahead and listen to the version from MGS2, as well.