Halo: Combat Evolved
Master Chief, a genetically enhanced super-soldier, must defend humanity from an alien theocratic empire called the Covenant while uncovering the deadly secret of the Halo ring — an ancient weapon of mass destruction built to stop an even greater threat. The game's open-level design allowed multiple approaches to each combat encounter, rewarding improvisation. Its two-weapon carry system and regenerating health shield created a demanding, strategic combat loop.
Halo: Combat Evolved proved definitively that the first-person shooter genre could work on consoles with a gamepad, a debate that had seemed settled in favor of the PC mouse and keyboard. It was the killer app that launched Microsoft's Xbox into the market and established the template for the modern console shooter — the two-weapon system, regenerating health, and co-op campaign are all legacies of Halo's original design.
Microsoft entered the console market in 2001 with the Xbox at a cost of billions, needing a first-party killer app to compete with PlayStation 2 and GameCube. Bungie, originally a Mac developer that Microsoft acquired, delivered with Halo. The game's network multiplayer over System Link cables also presaged the emergence of Xbox Live, the first major console online gaming platform.
Ubiquitous broadband internet shifted the medium from solo play to massive persistent social worlds, creating entirely new genres and business models. The MMORPG, the competitive shooter ladder, and eventually the live-service model all emerged from this transformation of games into always-online social spaces.