You start with only your wristblades and a speargun. You have only one task here and it's to take down prey. It won't be difficult, use your camouflage and begin the hunt. You can use your thermal vision to have a better look at your targets. There are three humans total and they are harmless scientists. Try to kill them all before they spot you and run away.
Note: Don't forget to cut off heads of your victims by striking them. These are your trophies. You can cut a head during a fight or you can do it from the dead body. The predator's shout will indicate that you got a trophy.
Follow the tunnel. There will be one scientist, two guards (one on the ground and one on the ledge) and all scientists you've scared away on the previous opening. Despite some humans are armed now, they shouldn't be hard to deal with, just don't forget about all the tricks and gadgets you have.
Note: Don’' forget to replenish your health and energy after each fight. It's free.
Jump on the ledge or use the ladder and follow the tunnel until you come to a swamp. You will see two guards in front of you. Despite they stand with their backs to you, they might spot you somehow. Kill them and go ahead avoiding the water – it deals damage to you.
Note: Beware of water if you're going unseen. It will turn off your cloak.
Go to the central circular piece of the land and take down the scientist who might be hiding there. Beware of the dark-green plant, it will deal you damage if you step too close. You need to go up. You might see a creature standing on a narrow bridge up above, but it's your ally. Come closer to get a combistick from your fellow predator.
Follow the bridge and a small corridor to appear in a small grove. Nothing of interest there, so use the treetops to get to another corridor and to a bigger grove. At first you might think that it's empty, but there are three guards waiting for you ahead. You can rush at kill one of them compromising yourself and then deal with his friends as fast as possible using your combistick. Or you can snipe one of them with the spearthrower and hunt his friends being unseen.
When you're done, jump on a tree next to the guards and to the next stone corridor. Jump into the water. Your camouflage will be turned off, so as soon as you come out of the water, activate it. You will hear a shout about movement and two guards will come to inspect. Two more are just behind them. Get rid of all the four.
Now you're in another swamp. Head left. Two guards will see you somehow and start shooting. Don't worry, just make a few steps back and wait. Another predator will kill them. Go there and take a disk from your ally.
There is only one way – to three huge piles of sculls. One guard will appear from the cave ahead but he's easy to slay. Two more guards will appear after him. You can move ahead to the cave to continue the level or you can take a left turn to have more fun.
If you decided to turn left, you will face two more guards. After killing and likely decapitating them you will see a well with a ladder down. There are neither enemies nor weapons there, just a lot of notes that can be read. When you've finished studying the notes, go back.
Go through the cave to see a spiral way up and a waterfall. Follow the way up until you come to a bridge with two guards. Now as you're more familiar with your tricks and gained more weapons, there will be no problem hunting them down. The road further is straightforward, just go through a stone tunnel and either jump down or stay on treetops.
You're in another grove, but now humans know that something (you, to be precise) has killed their mates and try to make an ambush. Humans are in the ruins. There is a chance that humans will try to retreat don't minding you decapitating them if you stay invisible.
Go ahead through another stone tunnel until you arrive in a huge space with stone pillars and water ankle-high. Humans will be fighting aliens and not minding you yet. You can rush in and try to deal with all foes while they're fighting each other or stay in a safe stop and wait until only humans remain.
When all the enemies are dead, go ahead. The water will turn you visible. Prepare the combistick and move until you reach a dead end. An alien will jump from above.
Boss fight: Praetorian
This is not a regular alien, this is a really tough one. To begin with, only your combistick can pierce through its armor, so don't even try other weapons. There are no special tricks or hints there, just constantly wave your weapon while keeping the distance with this monster. Eventually you will kill it and the level will end.