From the Manufacturer

Half-Life 1 Anthology features four exciting tiles in one great compilation. Titles include Half-Life, Half-Life Blue Shift, Half-Life Opposing Force, and Team Fortress Classic.

Half-Life
Half-Life features an integrated storyline with stunning visual effects and a huge, sprawling environment filled with aliens determined to hunt you down and kill you. You no longer just point and shoot--Half-Life is a dynamic, plot-driven, complex world where you need to play smart to survive. Monsters have a strong instinct for self-preservation. They will duck, jump, hide behind barriers to avoid gunfire, and even retreat if feeling threatened. Superior AI drives these behaviors and they are different for each species. Plus you can choose from 18 different weapons, ranging from a crowbar to laser-guided rockets.

Half-Life Blue Shift
In Blue Shift, players are challenged to take on the role of the Black Mesa security guard and explore restricted areas of the mysterious government facility. Blue Shift also contains the Half-Life HD Pack, which automatically upgrades the weapons and characters of all the games in the Half-Life saga with new high-definition content.

Half-Life Opposing Force
Built upon the amazing technology and with the visceral action of the original, Opposing Force returns you to the Black Mesa Research facility as one of the military specialists sent in to eliminate Gordon Freeman. The new single-player experience included is massive and incredibly challenging. Opposing Force also contains a completely new arsenal of weapons and over 12 new multiplayer maps created by many of the gaming industrys all-star designers.

Team Fortress Classic
The hugely popular team-based multiplayer game, Team Fortress Classic, runs on top of the Half-Life engine.