Half-Life 2 Walkthrough - Chapter 3: Route Kanal - Man Hacks and a Steam Puzzle
The fighting intensifies as the Combine pump man hacks into the sewers. This section of the Half-Life 2 walkthrough covers the best tactics for fighting the man hacks blocking your path and getting past the steam puzzle.
Walk along the path quickly. The helicopter is still here and it will start an attack run in about 10 seconds. Move along the short distance and turn left back into the next sewer tunnel to take cover. There's some sheets of metal and barrels in your way. You can just move them or blow them up. Break the boards and enter the next station. It seems like things are a little rough for the railroad. He'll also give you a signal when the man hacks are coming.
Pull out your crowbar and meet your first batch of man hacks. These little flying saws rush the station, but they aren't that tough. Back into a corner and wait for them to come to you. Knock them away with a crowbar when they approach. Two solid hits will blow them up. Once the three or four man hacks are dead, climb the ladder and take the bridge to the little platform above. Grab the energy and ammo before you leave.
Through the Sewers
Go through the door the man hacks came through and you'll see another batch trying to get through a metal door. Fight these in the hallway. It shouldn't be too hard in the tight hallway. Just keep them in front of you and keep whacking. Turn the corner to see another batch. They are probably going to set off the explosives barrels in the hallway though, so take a few steps back and let the blasts knock a few out before you go through.
Go through the path and walk past the grate door to the outside. I'm sure you need more health, so go into the little storeroom with the dead citizens to pick up some health. Then walk back out and go through the door to the outdoor area. This is an ambush. Two soldiers will appear on the pathway across from you and six man hacks will cut through the roof. You could fight them, but why?
Run forward and break down the wood blocking the door across from you. Open it and keep clearing a path. Shut the door behind you to lock out the man hacks. You just skipped a pointless encounter. Go forward and kill the man hack that appears. Then keep going until you drop down into another canal.
Three more soldiers drop down, one right in front of you. Shoot him and grab the new machine gun. Try it out on the soldiers at the end. Move out to the next water area and jump right into the area with turbine. It will keep spinning in that counter-clockwise motion, but it shouldn't be a problem. Maximize your oxygen and then swim to the bottom left of the room and duck into the vent in the wall when there's an opening. Swim through and stop at the breathing point halfway through the tunnel if you need more air. Then just keep going until you come to the end of the tunnel.
The Steam Puzzle
Move along the pipe but don't run straight up to the stairs. There's a barnacle waiting to ambush you. Step out and kill it. Then kill the combine soldiers on the pipe. Keep an eye out for reinforcements and man hacks at your back. Run back along the pipe toward the steam. Get as close as you can and then crouch. You should be able to shoot the barnacle hanging over the steam. Once it's dead, run past and stop again. Clear out the other two with gunfire or the explosive barrel. Then cross over the steam pipe while watching the man hack at the end. Just shoot it from a distance.
Get to the end and break down the boards. Drop down and crawl under the pipe to get some ammo and health. Then turn around and drop down through the flooded hole in the floor. Swim out to arrive at another canal battle.