Third dungeon. I can't open the last block with a keyhole in it to go down the stairs towards the master room because I need one last small key. However, according to the map and compass none of the rooms still contain secret chests. I already did the feather + boots combo to get to the chest on the far right. Is it possible I opened a wrong door and am now stuck? Walkthroughs gave me nothing.
Seems like on most playthroughs I had trouble finding one key. I forget what it was about the design. Yes, it does have 1 extra key. Many Link's Awakening dungeons seem to have small difficulties like this or strange little things (like the fear about the Eagle's Tower orb or the need to re-enter Tail Cave to enter the hidden room).
Some dungeons have better names in the original language (Japanese), some have better names in English. In LV3's case, the Japanese name is more fitting- Key Cellar. Looks a lot more like a gloomy (slimy) cellar than a cave, especially with those brick block walls.
If I remember correctly..The extra key is there in case you open the door that leads to the stairs before you open the door that leads to another key. So that way you can go back and open the room that has the key.