- "Well done, brother! Make free use of my traps, but take care not to fall in them yourself. In Ravenholm, you do well to be vigilant."
- ―Father Grigori[src]
The car trap consists of a damaged car attached to a system of pulleys, connected to an engine that lifts the vehicle above the ground. With the pull of an attached lever, the car drops to the ground violently, crushing anything below it. The engine attached to the mechanism then starts up, and the car is automatically hoisted back into the air, ready for another drop.
Apart for being used to kill Zombies, the car trap also helps Gordon Freeman to reach areas that would otherwise be inaccessible, serving as a sort of mock elevator.
Located near a propane trap, it prevents anyone from reaching the higher levels of Ravenholm, causing electrocution when touched. It consists of elements reused from a power plant and installed on a metal scaffolding touching a fence, with further elements also attached to the fence itself. To pass it, one has to use a lever to turn it off in the building facing it. Afterward, one can reach the other side by climbing a ladder hanged to the fence, then proceed to the roofs.
The propane trap consists of a large tank of propane with a hose leading out of a valve on its side. When the valve is turned, propane begins to flow out of holes in the hose and fill the immediate vicinity. A red switch nearby creates a spark that will engulf the area around the hose in flames and burn anything in its path (this can also be achieved by firing bullets into the gas cloud). The fire will continue to burn until the valve is turned again, cutting off the gas.
Propane traps are extremely effective against Zombies and Headcrabs due to the fact that the fire not only does damage to them, but also slows down their movement dramatically and allows them to set other creatures on fire. While they are on fire however, they can do significant damage to Gordon simply by running into him (notably Zombines), and burning him.
The propeller trap is made of a car engine turned on its side with a metal pole sticking out of it, connected to a very sharp piece of sheet metal on one end, and a counter-weight on the other. It kills any enemy instantly, most of the time cutting Zombies in half, and deals massive damage to the player if he walks through it. It is activated by ducking under the blade and pulling a lever. Once the blades are spinning, the only way to get around it without any damage is to duck and crawl under it. It is also advised to stay beneath it to lure enemies into the blade without being damaged by them. At some point during the Ravenholm chapter, a propeller trap will fail, leaving the player being assaulted by Zombies from many directions, although the Gravity Gun can be quickly used to throw the fallen blade at the assaulting Zombies, using it like the numerous circular saw blades found around the town.
- The lever on the "defective" Propeller trap is put on backwards. This is most likely a developer oversight.
- It's safe to release the crouch key while under spinning blades as the player does not stand up automatically unless the player press jump button or until the blades stop moving.
Behind the scenes
Other traps were to appear in Half-Life 2, some of which not only in Ravenholm, but were cut before its release. Most of their models can be found in the playable Half-Life 2 Beta files.
- The "crush trap," with unknown effects, was recycled in the Half-Life 2 canals, where it is used to hold the springboard that Gordon must rise to proceed to the next area with the Airboat.
- The "scythe trap" was to involve metal plates mounted on a pole and used as a scythe.
- The "till trap" was to be found in the canals and to involve a huge drill spindle.
- Actioned with two big wheels, the "guillotine trap" was to be a huge metal blade cutting its victims in half.
- The "catapult trap" was to be a solid metal catapult planted into the ground, sometimes sending the victims into a nearby wall when sharp objects could be planted.
- As seen in concept art not featured in Raising the Bar, the "pendulum trap" was to involve a tractor truck attached to a cable that would fall into the opposite wall, crushing its victims between it and the wall. A variant was to involve two vertical posts attached to an horizontal one at one side, and on a wall at the other, featuring two blades. When the wall attachment was to be cut, the two blades where to meet and cut in half the victim present in-between.
- A variant of the propane trap can be seen in the playable Half-Life 2 Beta, in the map "
d1_town_03". The player must lure Zombies into a small courtyard, close its two gates with levers and engulf the area in flames with the same system.
- The WC mappack contains a folder named "town_traps", where several demonstration/zoo trap maps can be found. They were made to show to the rest of the team how they were to work.