Password: TRDR
First, have Olaf walk right and glide down the shaft with the spikes. At the bottom is a zombie Baleog. Stand on the left side of zombie Baleog and face right to block his attacks. Now switch to Baleog and have him walk left of the starting position and fall onto the conveyor belt. Shoot an arrow left to hit the target so he can descend further, and when he gets to the bottom grab the blue key and walk to the right. Baleog should be able to fire arrows through the hole in the wall to hit zombie Baleog. Once zombie Baleog is destroyed, have Olaf stand next to the wall so Baleog can give the blue key to him. Switch to Erik and have him jump to the teleporter to the right of the starting position, and once he teleports jump to the ladder. Erik can jump from ladder to ladder but be sure to press the jump button before moving right, or he will just fall off the side of the ladder. Use the ladders to go right, get the red key and climb down the ladder there. Go left to the wall past the teleporter and have Olaf walk to the same wall so Erik can give him the red key. Now have Olaf use both keys and glide down to get the gold key and descend the shaft. When Olaf reaches the bottom, have him wait there and switch to Erik. Erik must go through the teleporter and then climb the ladder to reach the moving platforms. Jump across them to head left, and descend that shaft to get to Olaf's location. Switch to Baleog and have him go through the teleporter and walk right to join the other two. Before using the gold key, position Olaf's shield over his head and have Baleog spring onto it. Move Olaf and Baleog to the right so Baleog can reach the shaft that is covered by the white blocks. Now make sure that neither he nor Erik is standing on the white blocks, and have Olaf use the gold key and glide down past the spikes. At the bottom, walk right and climb the ladder to block the creature there. Now switch to Baleog and have him fall down the shaft where he will be saved from harm by a springboard at the bottom. Walk right and quickly descend the ladder so he doesn't get killed by the flying 8-balls. Kill the creature that Olaf is blocking, then have Olaf climb the ladder to block the 8-balls so Baleog can shoot the target. Now Baleog and Olaf can descend the ladder and go right, where they can reach the blue keyhole and wait for Erik. Have Erik walk to the left of the gold keyhole's location and jump over the teleporter that Baleog used. Fall down the shaft on the left to get the blue key, and spring up and right. Here he must jump off the platforms that constantly descend so he can reach another teleporter. This one takes him to the exit, but he has to give the blue key to one of the other vikings so they can use it to open the door before they can reach the exit as well.