Half-Life 2 Walkthrough -> Radioactive Waters
Along the way, you'll occasionally see a yellow lambda sign in a circle. This signifies a secret location nearby, where you can find some health and weapons.
We head to the old red hangar. But a headcrab rocket has already crashed there, turning the people into zombies. There's some health in a cage above the water—to reset it, you need to go up to the attic and knock out the barrel holding the mechanism:
Further along the canal, you'll come across a bridge where a man will drop off some health. Beyond the bridge is a ramp that needs to be raised. Climb into the pipe and emerge above a square pool.
Drop the blue tanks you find nearby into it. Then, dive underwater with each one and release it under the cage. Once all three have been transferred there, the ramp will rise and can be crossed in the airboat:
Breaking Through the Broken Gates
Navigating through the canals isn't particularly difficult. The main dangers are the Lizards hanging from some of the spans and the harvesters firing from the banks. When we reach the closed gates, we need to disembark at the canal's bend. There, we climb the stairs and navigate through the rooms until we reach the gates.
The valve that opens them isn't working, but behind the fence, along the canal, there are red barrels under a lantern. After we shoot them, the suspended weight will smash the gates:
Escape from the Stormtrooper
The next gate will close in front of us. It'll be in the area where the containers are parked on the shore and a helicopter flies over the water. Note the turret on the corner next to the gate – it's where the switch that opens it is. Swim to the pier in the "grotto." There, we knock the lock off the door and, finding a magnum, exit to the containers.
Avoiding the firing helicopter and fighting the Combines, we make our way between the containers to the building labeled "Equipment." There, we climb onto the balcony along the perimeter and then, passing through the building, we emerge back onto the street, where the tower is just a stone's throw away.
We climb up the stairs and press the red button to open the gate. Then we descend, disembark, and return to the boat.
Meeting the Allies
From this point, the helicopter will pursue us relentlessly, firing at us and dropping explosive barrels along the way. There will be a spot where, after a high ramp, we'll fly past a hangar. I recommend driving inside; you can find health and armor chargers there, and then take the boat down the elevator into the water.
To raise another ramp we encounter, we need to drop the washing machine on top of the descending cage. Go back a bit – there will be a ladder leading up between two concrete pipe blocks. There you need to walk along the walkway to the balcony and throw the washing machine from there – the ramp will rise:
Next, rebels are waiting for us in the tunnel. We go out to the shore to join them. We talk to the man. We go into the room. He tells us that Eli is waiting for us on the dam. Meanwhile, a Vortigaunt welds a machine gun to the boat.
We take out the helicopter from the boat
We land and continue on. At the tunnel exit, a helicopter is waiting. We shoot at it, and it flies away. The next locked gate needs to be circled along the shore on the right. There's a section of fence there you can drive over.
Finding yourself in a "courtyard" with two armored vehicles, you need to maneuver and shoot both until they fly apart. Then, go around the red container and detonate the red barrel inside, which will open a path under the wooden platform along the perimeter of this courtyard. We drive through the container and jump over the ramp.
We emerge into a small body of water with islands. Here, a big battle with a helicopter awaits us. We shoot it down with our cannon. The boxes on the islands contain some health and armor. It's best not to attack head-on, but to fire at the helicopter from the sides and below:
After killing him, drive through the gate marked "Port 5." Leave the boat there and head to the building with a large health pod. After passing the building, walk along the walkway to the dam. Turn the lever to open the gate. Return to the boat and jump through the gate from the ramp.
Afterward, you'll be introduced to the "Eastern Black Rock" laboratory (Black Mesa).
Source: antonioracter.narod.ru