Physics Manipulation

In Half-Life, it's possible to manipulate most of the moving objects by using one of the methods below. Using them you can Stop, Slow down or Reverse the movement of an object.

Hornet Gun

Probably the best weapon for physics manipulation is the Hornet Gun. It can do all the tricks mentioned above.
It's useful for:

• c3a1 (first map of "Forget About Freeman!") start, stopping the rocks that are falling down from the ceiling.
• Reversing the elevators and/or doors in order to make them close faster (and trigger the changelevel faster).
• Temporarily slowing down/stopping any moving object.
• Use to quickly move to Xen(Pass portal to Xen)(с3a2d)

Satchels

You can drop two satchels on any moving object or below it so the satchels will be blocking it's destination.
Useful for:

• Stopping any moving object.

Tripmines

Although tripmines tend to detach from moving objects, sometimes they might reverse the destination of a moving object, such as an elevator.