You do not need to read the first sign at the holes. Also, at the sign you switch to the hookshot. You are able to jump with the boots over those holes. It might be faster. Try it.
Els I don't think I have anything to comment. Looks good. But I beg you to fix that anyway, it just doesn't look good;).
EDIT: For dungeon 8. You have watched my movies, haven't you? I have made the whole dungeon in one movie now
http://dehacked.2y.net/microstorage.php/info/1634/Dungeon%208.vbm
Of course, there are lots to be improved. I just wanted to show you the route:).
Always, when you enter a room with doors that will shut; if you jump you can avoid the time when Link's stands still, as you see in the beginning of the movie. The Lava Pit Switch, I guess it is faster to stop it before the last pit so you jump over it instead of walk. I guess this saves a few frames. When I'm clearing the holes to get the key, you shalls switch to the feather and jump around some for entertaining, and also, so you will reach the key before it bounch. Use the mambo to get back, if you use S&Q the switch won't be activated.
When coming back to the lavaroom, I guess you can jump so you get closer "the end". Try it.
I'm not sure which room is fastest to enter first at the statue with the key. You can try a different solution, may be faster.
It's really annoying to wait for the flying enemy to land... I haven't find a way to kill it els, can you?
You can come even closer the Nightmare's Key chest. My way is not the fastest one. Also, I'm not always using S&Q to avoid the text when opening a chest, don't know really why but... It is of course possible.
The ice rooms suck:). You don't need to go around the ladder once more, and you don't need the text to show up either.
But for the last ice room. I'm not sure my way is faster. If you can find a way to avoid the text it would be. Or els just jump down and shoot the ice block from below.