Level 4. Dark Woods of the Serpent

Start by sliding down a ramp into a training area. Use the dojo if needed.

Climb the ladder and stay there, eliminating enemies.

Go to the East and West rooms, hit the switches at the end of each.

Return downstairs and enter the room between the katanas. Hit switches 1 and 3 (skip the middle one).

Go back upstairs to the East and West rooms and hit the newly revealed switches.

Obtain the BRONZE KEY.

Return downstairs and proceed through the bronze door using the BRONZE KEY.

Enter the Dark Woods and proceed to a house. Kill the rippers.

Find a crack in the upper right of the house entrance. Blow it open and enter to find and hit a switch, deactivating fire traps.

Re-enter the house and grab the GOLD KEY.

Return to the area near the bronze key door. Find a tree with a hole and enter it.

Use the GOLD KEY on the large doors leading to Peasant Village. Follow the path.

When the path splits left and right, take the left path to a well. Dive in and surface on the other side.

You are now in a red key house. Hit the switch next to the picture to reveal the RED KEY.

Take the RED KEY and exit the house.

Head left, then right, and find another red key door. Use the RED KEY to enter.

Enter the house labeled "Chin Sikki's Forest Fresh Rabbit Farm". You can find Uzis and rabbits here.

Head back out and take a left, then the first entrance to the left to find a fortune cookie.

(Optional) If you need a REPAIR KIT: Head back out, take a left, then a left again, then turn right. Look through a window, blow up the barrel to create a crack in the door. Go back around, enter through the cracked door, and use the lever. A northeast door will open, leading to the repair kit. You can dive into the pool for shurikens.

Proceed through the semi-circular tunnel into an open space with a steamed vehicle.

Use the repair kit on the vehicle. Defend yourself from incoming enemies.

Position the tank and use it to blow open the wall in front of you (requires 4-5 blows).

Go through the opened wall, kill the Coolies, and blow up the entrance crack to enter the house. (Optional: Collect ammo and items by going around the house).

Inside, collect grenade ammo. A teleporter will be revealed. Go through it.

You'll arrive in Ripper Valley. Turn right and proceed to a climbable mini-waterfall.

Kill all rippers in the area and jump out the wide opening on the left.

Turn right and jump on the carpet.

Ride the carpet until you reach an area with Coolie Ghosts and Rippers. Kill them along the way.

Get off at the last stop and head up the path, killing Rippers and Coolies.

Use the lever to reveal two remote-controllers for the arrow pillars. Adjust the pillars to allow passage from the left to the northwest.

Once across, go down the path, kill the ripper, collect items, and jump down the opening into the Serpent's Lair.

To defeat the serpent boss: Strafe frequently and maintain distance, especially with the Missile or Grenade Launcher.

After defeating the serpent, a cinematic will play.