
In an early Half-Life: Blue Shift trailer, a handheld version of flashlight acting as a unique weapon slot item can be seen. Rather than projecting a point of light, it simply illuminates a limited area around the player, similar to how the night vision functions in Half-Life: Opposing Force. In the Half-Life Alpha, the HEV Suit's flashlight acts in a different manner. Additionally, Combine Grunts can be seen using flashlights when investigating the ruins of the Vault's crash. Combine Ordinals also carry flashlights as part of their gear. She attaches this flashlight to her Gravity Gloves, and Russell informs her that it's sensitive to darkness and will automatically turn on in low light environments. The name on it indicates its brand is PocketFLASH. In Half-Life: Alyx, Alyx Vance acquires a flashlight from the corpse of a Combine Worker while in the Quarantine Zone. He states that he was told he would die if he were ever to turn his flashlight on. This is demonstrated by Wheatley in Turret Manufacturing when the power to the wing is shut off. In Portal 2, the Aperture Science Personality Constructs are shown to have built-in flashlights projected from their eyes. In Half-Life 2: Episode Two, the flashlight was given a separate power source that had previously been shared with the sprinting and oxygen meters. Zombies hidden in darkness are instantly attracted to the light source, and Fast Headcrabs clinging to the ceiling in ambush will immediately strike if a light shines upon them. Half-Life 2: Episode One features a segment in which Gordon and Alyx must travel through pitch-black underground tunnels overrun with Zombies using only his suit's flashlight and flares for illumination. However, the invading HECU and Black Ops forces instead opt for night vision goggles, the former as a part of their Powered Combat Vest outfit. The science personnel in the facility are also seen wielding a variety of portable light devices. Black Mesa security guards carry handheld flashlights that function in the same manner.

If kept on for too long, the flashlight will automatically shut off once it depletes its available power.

The flashlight slowly drains its energy supply while in use and recharges when turned off. The HEV Suit includes a built-in flashlight that runs on an auxiliary source independent of the suit's power supply, allowing it to be used even if the suit is fully drained. First formally introduced during the Hazard Course training, the flashlight is a tool used to illuminate dark areas, such as through Black Mesa's numerous ventilation ducts.
