Developer(s) Gearbox Software Release date(s) June 12, 2001 [1] Genre(s) First-person shooter Mode(s) Single-player Platform(s) Microsoft Windows Rating(s) ESRB : M (Mature) Distribution Sierra (previously), Steam System req 500 Mhz processor , 96 MB RAM , and 16 MB video card Input Keyboard and mouse Engine GoldSrc Series Half-Life Designer(s) Randy