Start the level off by grabbing the two clue bottles on the left side of the path, then climb the pipe on the side of the gate up to the top. From above you'll see that Mesa City is no longer a thriving boom town, but a desolate desert city. You can use the new Ninja Spire Jump to go from point to point on the wire to get over the enemy below. Although you can pass him up, you'll want to head down there to grab the bottles. Jump down on top of the enemy for an easy kill and get the two bottles beside him. Back up the path toward the front gate you'll find another bottle on the side of the path and a safe with two more bottles. You can either climb up the pipe to the wires overhead, or just double jump around the rock blocking your path to continue on.
In the next section, smack the dog on the leash then grab two more bottles nearby. Instead of using the mattress to get on top of the shack, jump out across the wooden objects floating on the water. They'll take you around in a circle letting you collect four more bottles. You can use the rings at the end to swing back to where you started. Use the mattress to get to the roof of the building, then climb the pipe and jump to the swing to get to the other side. After the dog, be careful because when you get close to the wooden fence behind him, an enemy will bust through. Take him out then grab the three bottles behind the broken fence. When you jump up on the hanging magnet, Bentley will explain how the flashing floor light security works.
Before heading into the subway car, run out on the wooden beam going off the side of the cliff for another bottle, and break open the safe next to the checkpoint marker. When you get through the subway car there are two more bottles on the right just as you come out. You can easily take out the ball and chain enemies by running up and jumping over the ball they swing at you. Head up the rocks on the side and take the mattress up to where you can Ninja Spire Jump across the wire to a teetering rock platform. These throwing card enemies are a little faster than the ball and chain ones, but the same strategy applies—run up and jump when they throw. Grab the two bottles up there then drop off the other side to the tire stacks. If you turn the camera back around from on top of the tires, you should see a well-hidden bottle behind the car on its side. Jump down there, then double jump around the side of the car to continue on.
Break three more bottles behind the wooden fence before dealing with the roped up dogs ahead. If they give you problems, just wait for them to snap back to the post they're tied to before running up and killing them. Grab the single bottle on the side before heading through the crusher. Get the lucky charm on the car, and when you get close to the fence after the car, another enemy will coming crashing through. Break the safe behind the fence open, then move on to the next one, where two enemies will come through. Before going through the next crusher machine, jump up onto the hanging magnet for three more bottles.
On the other side, take out the ball and chain enemy, then turn around and grab the bottle on the side before heading through the next subway cars. Just take your time and wait for the lasers to group up and watch for when the floor lasers start flashing. After the first security alarm, you'll need to swing across two hooks to the next car and continue on. When you get through and take the pipe up to the end area, double jump the card thrower's attack and take him out. There are two bottles behind the fence and one in front, and a safe off to the side. When you get the last bottles, you'll need to backtrack quite a ways, but it shouldn't be too difficult with the security off in the subway cars.
Head back past the last crusher machine and use the car that had the lucky charm on it to jump up to the rope above. It will take you out to the safe where you can use the code, then return all the way to the end of the level to grab the key there and move on.