Nidhogg's control assignment screen and "how to play" menu option are rather... uninformative. Sure, I can move and jump and attack, but the controls clearly do far more than is immediately apparent; for instance, holding up and pressing attack will throw your sword. There also seems to be some condition under which you can disarm your opponent (or be disarmed yourself), but I have no idea when that happens.
So what are Nidhogg's actual controls? What sorts of moves can I do under which circumstances by entering in a series of inputs?