Chumpland.org
A Half-Life and Opposing Force multiplayer guide covering essential deathmatch strategies.
Gameaholic dot com
Cheats, console commands and variables.
GameSpots Half-Life Game Guide
Guide to weapons, creatures, cheat codes, and walk-through for Half-Life.
GamingHaven HTML Walkthrough
A HTML level-by-level walk-through for Half-Life.
Half-Life Power Page
Console commands, hints, FAQ, and walkthrough.
Half-Life Zone
Contains a small assortment of pictures, links, and a walkthrough.
UHSWeb
The Universal Hint System gives information to help solve the game.