FIRST VISIT - AFTER TOMB OF SOBEK: After defeating Sobek, you return to the Overworld to find it covered in snow. Cross the newly formed ice bridge on the west side of the Shrine of Osiris to enter the Cliffside area. (screenshot)
Unlike the Shrine, this entire area is accessible regardless of the weather. We won't explore the whole thing yet, but we will make a few pickups on the way to the Tomb of the Torturer. Start by moving forward (west) along the walkway until you come to a short flight of stairs with columns on both sides. Jump onto the first column and then jump over the crossbeams, gathering a few gems in the process, in order to reach the first red skull (1/5). (screenshot)
There's a MAX HEALTH UPGRADE sitting in a barred alcove in the corner above and to the right. In the co-op game, you can get it right away. Just have one character stand on the pressure pad on the ledge to the right to open the gate while another retrieves the upgrade. (screenshot)
In the single-player game you must find a weight to place on the pad. Head to the south, past the giant, broken statue, and you'll spot a large metal ball on a plateau to the right. Go around the bottom of the plateau to find a ramp leading up to the ball. Grab it and push it off the top left edge so it lands near the broken statue. Push the ball close to the ledge with the pressure pad and then use a remote bomb to launch the ball onto the pad. This holds open the bars so you can reach the upgrade. (screenshots)
Now head to the south, past the huge, broken statue and one of the golden statues of Osiris. In the single player game, you'll want to bring the metal ball with you. Just below the statues on the right is another pressure pad. Move the ball onto the pad to open the gate below. On the way down the stairs, pick up the red skull (2/5) by first jumping onto the shorter column near the pressure pad, then the taller one with the skull. Continue downstairs and around to the left. Carefully hop out onto the scaffolding and pick up the MAX AMMO UPGRADE in the alcove. In the co-op game, one player can stand on the pressure pad while the other retrieves the upgrade. (screenshots)
Roll the ball down the stairs. Then follow the footprints in the snow to the south. Try to avoid the rotating snowmaking machines, since the blast of cold will injure your character. If you don't have a cold-resistance item equipped, it will also slow your movement temporarily. Roll the ball near the column between the 3 machines and use it to reach the red skull (3/5) on top. In co-op mode one character can reach the skull by jumping on top of another's shield. (screenshots)
Gather the gems in this area and then head for the lower right (southeastern) corner to find the entrance to the Tomb of the Torturer. Use the AMMO CACHE here if necessary before entering the tomb. (screenshot)
SECOND VISIT - AFTER TOMB OF THE TORTURER: As you emerge from the tomb and head to the west, a brief cutscene shows a door opening elsewhere (screenshot), and you receive a new Objective: Explore the Pharaoh's Crypt in the Southern Cliffs. If you followed this walkthrough you also still have a separate goal from before: Retake the Piece of Osiris in the Tomb of the Architect. Both are marked on the Overworld map. (screenshot) It doesn't matter which you do first, but if you consult one of the Osiris statues, it will point you to the Pharaoh's Crypt.
NOTE: If you want to, you can detour back to the shrine to place Osiris's pelvis on its pedestal, but this is not necessary. When you return there later, after completing the tombs in the Cliffside area, all of the parts you found will be placed where they belong.
From the Tomb of the Torturer, head down the slope to the left, past the 3 snowmaking machines. Then climb the stairs to the upper left (where you found the MAX AMMO UPGRADE earlier). At the top of those stairs, continue to the left past a golden Osiris statue and another snowmaking machine. When you come to a broken walkway with a square tile with the Glyphs of Osiris below, drop down there. (screenshot)
FIFTH CHALLENGE TOMB: Here is the entrance to the next Challenge Tomb. It is marked with a star on the Overworld map. (screenshot) You can explore it now or return later. The FIFTH CHALLENGE TOMB WALKTHROUGH is on a separate page. When you complete all five Challenge Tombs, you are rewarded with a MAX AMMO UPGRADE in addition to the goodies you find inside the tomb. You'll also unlock the "I love tombs!" Xbox/Steam achievement.
When you're ready to move on to the Tomb of the Pharaoh, head to the south until you come to another snowmaking machine. Move past it and continue to the left. (screenshot) Then head up the steps to the south onto a small plateau with a HEALTH SHRINE. (screenshot) Make a pit stop here before going down the curving staircase on the left to the tomb entrance. (screenshot)
THIRD VISIT - AFTER TOMB OF THE PHARAOH: When you emerge from the tomb after defeating the Pharaoh, you are reminded of your next Objective: Retake the Piece of Osiris in the Tomb of the Architect, which is marked with a yellow dot on the Overworld map. (screenshot) It is now nighttime, and as a result a 1,000-gem treasure chest has appeared to the right of the tomb entrance. If you can afford to open it, you might get something nice. (screenshot)
Head up the stairs to the left. Go down the stairs beyond the HEALTH SHRINE and climb onto the low ledge ahead. Just before the next snowmaking machine, head to the left. In the single-player game there's a grapple ring here, which you can use to climb down over the edge and retrieve a red skull (4/5). In the co-op game there is no ring, so one player needs to grapple another and lower him or her down to the skull. (screenshots)
From here, head up the stairs to the left of the snowmaking machine to reach the entrance to the Tomb of the Architect. The door is sealed, so you'll need to find a way in. First, move onto the tile with Osiris's Glyphs near the AMMO CACHE to the left of the doorway. Use the staff to extend a column so you can reach the last red skull (5/5). In co-op you can either use an Egyptian character's bubble shield to boost another character onto the ledge or climb up the round steam vents to reach it. If you've found the other skulls as well, you will now receive the BRONZE RING OF STRENGTH (Weapon Damage+, Bomb Radius+). (screenshots)
OPENING THE TOMB OF THE ARCHITECT: Climb down and stand on the square pressure pad (in the co-op game there are 2 pads) to receive a message about a new minor Objective: Bomb Free the Four Frozen Gears. This isn't much of a challenge since the text tells you what you need to do, but in any case, start with the giant gear (1/4) to the right of the pressure pad. Either detonate a remote bomb near it or just melt the ice with the flamethrower. Hop down off the ledge and head to the right to find the next giant gear (2/4). Destroy the ice around it with the flamethrower or a remote bomb. Move downscreen and climb down onto the next giant gear (3/4), just to the right of the Challenge Tomb entrance. Drop a remote bomb on or near the gear and get out of the way before blowing it up to free the gear. Use the column with Osiris's glyphs to climb onto the ledge on the left near the wooden scaffolding. Destroy the last giant gear (4/4) to open the Tomb of the Architect. Climb the stairs on the left or the scaffolding on the right and enter the tomb. (screenshots)
FOURTH VISIT - AFTER TOMB OF THE ARCHITECT: As you exit the tomb, you'll receive a new Objective: Return to Osiris's Shrine and Banish the Cold. Head back to the northeast. (screenshot)
COMBAT CHALLENGE: When you defeated the Pharaoh earlier, a glowing obelisk appeared in the open area near the fallen statue. (screenshot) Rather than including it in the third-visit section, above, I decided to mention it here since you'll pass it on your way back to the Shrine. If you like, you can approach the obelisk and press the button indicated to take on an optional Combat Challenge. Defeat the enemies that spawn to earn a reward. For more about this feature, see the Community and Combat Challenges page.
Continue to the northeast and return across the ice bridge to Osiris's Shrine. (screenshot)
†UPDATE HISTORY: 1/11/15 - First draft of walkthrough posted.
1/19-31/15 - Updated as new sections added.
6/26/15 - Finally back to work on this after a much-needed hiatus. Added the fourth visit section, completing this area.
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