Doom (1993)

Doom (1993) is undeniably the progenitor of the modern first-person shooter, establishing fundamental conventions still prevalent today. id Software's revolutionary title introduced fast-paced, visceral combat and iconic level design that captivated a global audience. It was instrumental in popularizing PC gaming, selling millions of copies and generating an estimated $100 million in its first two years alone, significantly more than its contemporaries. Its shareware model, distributing the first episode for free, was a novel approach that rapidly expanded its reach, a tactic rarely seen with the same impact from later titles. Doom's influence is so profound that many subsequent FPS games, including later entries in this list like Half-Life 2, owe a direct lineage to its foundational mechanics and design principles.