Finished this quest (only 1 more to go :-) anyway, my quick rundown: (Note: since there seem to be many versions, I played the one with file dated 1/25/14)
With the exception of a couple rooms in level 6, this was a very easy quest. Enjoyable, but I don't think it is suitable for a 5th quest. Starting with the fact that there are 7 heart containers on the surface, this means that you could, in theory, get the magic sword after dungeon level 3 (some heart containers require the whistle, so you can't get it after dungeon 2,since you won't have all 12 hearts available; but after dungeon 3, you could have 13 hearts) I don't know if it was deliberate or not, but you are maxed out at 16 hearts, so you won't go to dungeon 9 with 18- not that you'll need that many.
There are several problems on the overworld- most of which have been mentioned before, but I will point out 3 specific problems: (1) In the screen 1 North and 1 East of the starti screen, there is a door repair which has the new sword message ("master using ..."). (2) On the screen 1 North of level 7 in the 2nd quest, there is an empty cave. (3) When you exit dungeon 5, you go to the screen 1 West of the SE corner.

There were a few dungeon problems (as opposed to things I didn't care for):
The NE corner of the graveyard has a tombstone that doesn't release a ghini. I spent a lot of time trying to open the path here. Only when checking the editor did I find that the dungeon entrance was elsewhere, but this location has the upgraded-bomb-required flag set. There are no upgraded bombs in this map.
In dungeon 7, there are 1 too few keys. In the editor, it seems that there is supposed to be a key located in room 46, but I never got one there. Also, as a result of this, since you cannot go back to the entrance from this area, you can be forced to f6-continue. Particularly nasty is that this room (46) had red bubbles, but there are no blue bubbles in this whole section of dungeon.
The only other criticism I have is the incredible number of underground passages in level 9 - 42 of the screens have an underground (4 are networked, the other 38 are paired), and as mentioned by another, one of them- room 42- goes to room 65, but room 65 goes to room 42 in dungeon 1, not 9!

I didn't see much new in the creatures, but since some I only saw in other 5th quest entries (such as the fire-zols), I will still give credit to them (I can't honestly penalize someone because of the order I happened to play the quests!), but the bosses, however, were all from the main 4 quests. The only unique to this map creature (AFAIK) is the quad-patra, which was actually easier than most normal patras.

Anyway, the map is overall decent, but definitely not what I would expect in a 5th quest. I give it an overall rating of 2.86 out of 5.