they already have the technology to make HUD's like MC has in his helmet. Most of the things about Mjolnir we have now. they just aren't strong enough. and we don't have shield capabilities, but then again in halo neither did the UNSC until they stole the tech from the Covenant. we can augment different things about people genetically before and after birth. not as much as the Spartans but it will be like that some day. and we have suits that make you stronger but not as simple as the Mjolnir. they are bulky.