Paranoia: The Game

Description
Paranoia: The Game is an authorized port of the Half-Life mod Paranoia to the Xash3D engine, making it a fully standalone game without the need for Half-Life to be installed.
In Paranoia, the player controls Major Alexander Kalashnikov, a soldier in Russia's Federal Security Service who has just spent six months in a hospital in Siberia recovering from an injury. In his first assignment back in the field, Alex is dispatched to repel a terrorist attack on an industrial complex that once housed an important scientific laboratory. Upon descending into the laboratory, Alex discovers that it contains horrors beyond human comprehension.
The game is a horror-oriented first-person shooter which features a variety of realistic weapons to use against enemies, as well as other gear which affects gameplay, including a retractable ballistic face shield that greatly reduces incoming damage to the head and a gas mask that protects Alex from toxic gases. Alex can walk over health kits to instantly restore his health and pick up armored vests to repair his armor. Painkillers can also be collected and saved for later, restoring a small amount of health when consumed.