I've just entered Level-7, and made a b-line for the red candle. Everything is going suprisingly well, though I've already used my first potion, so the clock is ticking here. I'm not really sure is I'm just better, or if time away has cleared my mind, but I was intimidated to come back because Level-6 was a particularly frustrating dungeon for me a few months ago. In contrast, Level-7 has been a breeze so far. Hope I don't jynx myself!
I've stumbled upon a room with a familiar enemy set up, so it might be good to talk about.

I don't remember how it is in first quest, but in second quest, you'll regularly find rooms like this. It'll have some sort of arrangement of darknuts in a room with limited maneuverability, and then it will throw in both blue and red Bubbles. This is a really great example of how Zelda 1 manages to have very difficult combat while remaining completely fair. The rules before you are very simple. Red bubbles disable your sword while blue bubbles enable them. Both cause hit stun, but both are otherwise harmless. The "puzzle" comes in navigating around the red bubbles while trying to land precise hits on the already difficult to hit Darknut enemies. The layout of the room makes landing more precise hits all the more frustrating. The player must accustom themselves to the fact that the red bubbles are the most terrifying aspect of these rooms, and getting hit by one always results in a frustrating panic to chase the blue bubble while defenslessly avoiding the darknuts while maneuvering yourself through such a restrictive room layout while also avoiding knockback from bubbles that may knock you into a darknut by mistake.
The rules are clear, but the punishment is swift. Totally fair, but totally frustrating. I love it, even if the gimmick is getting old as the puzzle gets repeated and Link grows in power and defense.
EDIT: With how powerful Link is by this point, I was able to clear the room in a matter of seconds, but when Link was less powerful, this set up was absolutely the most difficult room type in the game, taking me multiple tries.
