Unarmed(no effect): press 1 to interact with npc/item, press 2 to pick up/put down npc/item, press 3 to talk to npc(talk bubble appears overhead), press 4 to attack npc/item(cannot kill, only stun), press 5 to show affection toward npc.
Katana: works like knife, press Z several times to do a multiple hit combo.
Gun: press Z to shoot straight, or press 1 to make a crosshair appear(use directional keys to move crosshair, Z to shoot, and 1 again to cancel).
Shovel: press 1 to dig(has 1/3 of digging up a coin, and can be used to trigger an event).
Remote: Press 1 while in front of npc to control them(1 again to cancel, try pressing keys to try stuff).
Rope: press 1 to throw rope forward, if it connects to an npc/item press 1 to cancel, the directional key you're facing to move toward the npc/item, and the opposite key to pull them toward you.
Instrument: press 1 to take out instrument, 1 to put away, 2 to toggle between instruments, and Z to play a note(hold directional keys while pressing Z to change tone; upZ=very high, >Z=high, Z=normal, <Z=low, and downZ=very low,)
Fan: press 1 to swing fan, all onscreen npcs will be pushed in the direction you're facing(by about 4 spaces).
Pretty: npcs will show interest in you, and hostile npcs may act friendly(you act the same as Unarmed, press Z to sparkle).
Dirty: npcs will try to avoid you, and friendly npcs may act hostile,(you act the same as Unarmed, press Z to scratch head).