You begin on the right side of the forest. After passing a bar, you will begin to encounter projectile-tossing enemies; goblins in the SMS version, and stone throwing apes in the other versions. The apes do not drop money, but they are more likely to drop valuable inventory items or hearts. In the PC Engine version, they are particularly likely to drop the next level shield or shoes that you need.
Carefully proceed left through the apes until you reach the platforms containing snakes. Strike each snake as you make your way closer to the well. Jump inside the well. In the arcade and PC Engine versions, this will lead to a short segment where you fall down a shaft occupied by a couple of red spirits. They are unlikely to hurt you, but be careful anyway.
Bats will greet you at the bottom of the well. Deal with both of them before proceeding to the right.
You will now encounter the frustrating Mudmen. Mudmen slither back and forth along a short segment of floor, typically too low for you to hit. After moving back and forth twice, they stand up and spit mud at you. Your shield can deflect the mud, but the trick is to approach them and stab them before they drop back down to the ground. If you manage to defeat them, they often leave decent sums of money behind.
After you encounter three Mudmen, you may notice something on the ledge of the third Mudman (labeled "!" on the map). Push up on the right side of the ledge to discover a secret entrance. Behind the door, you will find a Kong, an incredibly difficult boss which guards the Great Sword. (If you don't have the Heavy Armor yet, jump down to the next step and then return here.)
The trick to defeating the Kong is very similar to the strategy employed against the Knights; aggressively rush Kong until he is force to leap over you and attack from the other side. The problem is if you leave Kong alone for too long, he will throw a boulder which hits the ground and fragments. You can block the fragments with your shield, but you'll have to turn around in order to do so. If you happen to have any special weapons at your disposal, it is recommended that you use them up during this fight. It is quite common to end up using medicine during this fight. Once you beat Kong, however, you will receive an upgrade to your offense in the form of a new sword.
Beyond the mudmen, two strong bats await you. Don't expect to kill them in one blow like you do with the regular bats; allow them to fly back up and return to attack you until they are defeated. Door B in the back is actually an armor shop. If you haven't bought the Heavy Armor yet for 100 gold, do so now. Then climb up the steps, preparing to fight one more strong bat, to exit the cave.
You are now on the border of Mam desert. Door C contains a bar, and if you choose to get a drink there, you will learn about a secret about the pyramid. Jump across the water to the desert.
A series of goblins are posted as guards in the desert. Deal with them as you normally would, deflecting their arrows with your shield and striking when you are close enough.
After you defeat the second goblin, and you proceed across the sand, you will drop through an invisible hole in the ground. In the absence of any boss for this stage, you will discover the key at the bottom of the pit, along with four strong bats. For each bat that you defeat, as well as for picking up the key, a new moving platform will be introduced. Once the key is collected and all four bats are killed, five platforms will sway back and forth, leading you back to the surface. Bear in mind that the timing is trickier in the SMS version due to the second and fourth platforms' shorter traveling distance.
Once you are back, continue heading to the right, defeating each goblin that you encounter along the way. Be on the lookout for arrows which appear on your left. Soon you will reach the gate at the entrance to the pyramid. (There is a stronger blue goblin waiting by the pyramid in the SMS version.)
