Clash at Demonhead/Route 2

Description
When you arrive (from the left), an enemy will fly overhead, shooting projectiles down at you. You'll reach a pit which you must jump over. If you don't, you'll fall down into a cavern which you must walk to the right or left in order to escape (It will send you back to whichever side you entered from.) On the other side of the pit are two small monsters who run very quickly back and forth across the surface.

Beyond those ledges is a long pool of water. You must swim all the way across to right the right exit. If you dive down, you will slowly lose some health. You cannot dive deeper into the water here. Enemies will fly overhead and shoot at you, but you can safely swim beneath most of them without having to worry about getting shot. Hop out to exit the route.