Zelda 1 - Walkthrough of Dungeon 4 of Quest 1: The Snake (Zelda I NES mini)
Map of the labyrinth "The Snake": Dungeon 4 of Quest 1 from Zelda I (The Legend Of Zelda NES mini)

In this dungeon you will encounter Vires for the first time — demons that, like the Zols, transform into two Keeses (bats) when you hit them. If you hit them with the magic sword, they die in one blow. You will also find many unlit rooms. Using the candle once is enough to light a room until you leave it. You will also encounter shield-eating Like Likes. If these monsters swallow you, hit as fast as possible — you might be able to kill them before they devour your shield.

Start by going left, killing all the bats and taking the key (1). Go back right and go up. Go right and take the compass (2). Come back out and go up. Take the key and go left. Light the candle and go up. Take the key and go up. Go right, kill all the Vires (3) and go right again.

Kill all the monsters and push the left slab (1). Go down the staircase, pick up the ladder and come out of the basement (don't hesitate to use the boomerang to avoid having your shield eaten by the Like Likes, especially if a Bubble touches you). Go back 2 squares left and go up. Go right to pick up the map and blast a hole at the top (2). Blast another hole at the top, take the key and go right. Go down, kill all the Vires and push the left block to open the boss door (3).

The boss is called Gleeok (the Two-headed Gleeok). He fires balls that even your magic shield cannot stop. To defeat him, you must hit each head 4 times. When a head "dies", it flies off and keeps firing balls at you.

Small Key : A6 - B6 - A5 - B1
Dungeon Map : B3
Compass : C7
Stepladder : C4

You are ready to continue the adventure. Here is a save file (an 8 KB .sav file).