For some reason these guys are really annoying. They just walk around, and you hit them a few times and then they're dead. Have fun.
Ninja Monkey
Ninja Monkeys hop around and don't stay stationary for too long. They take more than one hit to kill.
Bone Head
These guys will walk around and jump over water to get to you. They take a number of hits to kill. Your best bet is to stand behing some water and lay it on them while they try to jump at you.
Gad Fly
Gad Flies will fly slowly from left to right and then take a sudden quick dive at you. They're tricky, and take a few hits to kill.
Mad Muddy
Mad Muddies pop out of lava ant random places and throw bals of magma at you. They can also appear in water and throw water-balls(of death) at you.
Volcanos
These guys come in fours and fire magma-balls at you, four at a time.
Bone Dog
Bone Dogs run around and take more than one hit to kill.
Skull
These guys are like the Octots, but they take more than one hit to kill them.
Volcano (2)
These are just like the Volcanos, except that they can come in singles, but be away for they can come in groups as well. You can't kill them, but they can kill you.
Mummu
Mummus walk slow, but take a good hit out of you. They always follow you, so you should just stand far enough away from them and keep rackin' them with your yo-yo until they die.
Mini
Minis are invisible until you use the Rod of Sight, but be careful because they can still hurt you in their invisible state.
Dimhag
Dimhags will appear in random spots in the room and fire magic at you. You'll need a mirror to reflect their magic back at them to kill them. (something that Zelda had not yet done ;)
Mr. Armstrong
Mr. Armstrong busts out of the ground and throws rocks at you. Just hit him with your yo-yo a few time to kill him.
Gogglin
These little Gogglins float around the room slowly.. until you hit them! Then they'll charge back and forth for a bit.
Big Bully
Big Bullies are big and hard to avoid if one is able to corner you. They move slowly, but they have a big body which will take a good chunk out of you if he touches you. He takes a number of hits to kill.