Half-Life: Opposing Force (1999): runs on Windows 11, Mac, Linux, Steam Deck?

Gamicality score 93 / 100

Playability today ★★★★★ 4.5

Runs today5 / 5
Design today3.5 / 5
See the checks

Steam user reviews Overwhelmingly Positive

25,561 reviews95% positive
Steam store page

Released: 1999
Developer: Gearbox Software
Genre: Action
Runs on: Windows, macOS, Linux, Steam Deck
Last checked: October 31, 2026

Does Half-Life: Opposing Force run on Windows 11, Apple Silicon Macs, Linux and Steam Deck?

Windows 11	Expected to work. It is sold for Windows today and no problem is on record. SourceNo player reports yet
Mac (Apple Silicon)	Steam sells a Mac version. Not yet confirmed on Apple Silicon. SourceNo player reports yet
Linux	Yes, there is a native Linux version. SourceNo player reports yet
Steam Deck	Playable, as rated by Valve: it works, but may need some manual configuration. SourceNo player reports yet

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Synopsis

An expansion to Half-Life that retells the Black Mesa incident from the other side, as Corporal Adrian Shephard, a Marine sent in to clean up the facility. You fight through familiar and new parts of the complex with new weapons, alien factions and squadmates who can heal you or open doors.

What people say

Critics in 1999 treated it as a model for how an expansion should be done, praising its new enemies, weapons and the way it reframes the original story. Some reviewers felt it leaned too heavily on set pieces borrowed from Half-Life. Later players still enjoy its pacing and atmosphere, but point to weak squad AI, a tedious crate-pushing sequence and a confusing final boss. Steam reviews remain overwhelmingly positive.

Playability today

Playability runs from 1 to 5. It is the average of two parts. Each part starts at 1 and climbs to 5 as more of its checks pass. Read the method.

Runs today: 5 / 5

✓Sold today from an official store
✓Runs on Windows 11 without fan patches
–Single-player works without an internet connection
–All of its content still works (servers, DLC, unlocks)
–Supports modern resolutions and widescreen
–Full controller support or remappable controls
✓Steam Deck Verified or Playable
✓No intrusive DRM or required third-party launcher account
✓No pay-to-win or pushy microtransactions
–No known game-breaking bugs in the current version

Filled in from the Steam store and Valve’s Steam Deck rating. Checks marked – are unknown and do not count until someone checks them.

Design today: 3.5 / 5

✓Controls feel natural on a modern controller or mouse and keyboardMouse and keyboard play is as smooth as Half-Life itself, though controller support is only basic. Source: onlysolitaire.substack.com, pcgamingwiki.com.
✗Menus, text and interface are clear on today's screensMenus and interface text can be tiny at high resolutions and font size has to be changed by editing a config file. Source: pcgamingwiki.com.
✓Saving is fair: free saves or frequent checkpoints, little lost progressYou can quicksave and save anywhere, with Steam Cloud sync, so little progress is ever lost. Source: pcgamingwiki.com.
✗It teaches itself: no guide needed to make progressA boot camp opens the game well, but the final boss is unclear enough that players spend more time working out what to do than doing it. Source: onlysolitaire.substack.com.
✓Pacing holds up: little grind, filler or forced backtrackingThe short campaign moves steadily from familiar ground to new places, with one dull crate puzzle as the main lull. Source: onlysolitaire.substack.com.
✓Camera and movement never fight the playerFirst-person movement works as in Half-Life and no source flags camera trouble, though evidence on this point is thin. Source: onlysolitaire.substack.com.

Judged against games made today, from complaints that recur in recent Steam reviews and discussions, forums, PCGamingWiki and community wikis. Each reason links to where it comes from.