Haramaki-do just means that the armor ties up in the back. Do-maru fastens on one side. There were others, including fasteners on both sides, or in the front, but those were the most common. From the looks of that movie still, it's probably do-maru.
O-yoroi translates like "great armor", and was a partial plate armor used heavily pre-Onin War, but becoming increasingly ceremonial as lighter and more flexible designs that offered almost as much protection appeared. You can always pick it out by the heavy box-like trauma plates front and rear. (For the record, it is heavy, comparable to European combat plate, but it is not as stiff or clumsy as one might assume from its appearance.)
I can't remember the name for those helmets with the high rounded top (it's late and I don't feel like looking it up right now), but they're not that uncommon in Japanese history. The neck plates and eye guards look pretty standard. The horns are, well, about what you would expect from Japanese helmets ... nobody could do preposterous headgear like the Japanese samurai. Seems all their helmets (minus the ones issued to really low-ranking types) had ridiculous crests (often also in horn-like motif), deer or bovine horns, bizarre metal ridges, or sometimes all of the above. Some were even worse - animal skins or even sometimes entire stuffed animals over the helmet, or wings and plumes of feathers several feet high. Most had masks with them, of which only a few were seen in that movie - and the mask designs ranged from skeletons and old men to eagles to trolls to clown faces and bunny-rabbit motifs. (Hard to remember you're trying to kill someone when the only thought going through your head is "why is he wearing a bunny rabbit costume?" And terribly humiliating when you have to report that your squad was wiped out by what appeared to be a circus clown.) That helmet in the movie was actually rather conservative, by Japanese standards.
Honestly, I'll bet modern armies would get more recruits if the let soldiers decorate their helmets like that. "We may lose the war, but our helmets have HORNS!" Who needs better technology? We'll just scare the other side to death!
Scotland tried something like that as well, sending their troops to war wearing skirts ... or sometimes full dresses with beads and stuff on them. This was accompanied by a terrible noise, produced by bagpipes. It was, and sometimes still is, amazingly effective. If your enemy is freaked out badly enough, he will forget to fight.
