PC · 1998 · 3D Realms · 3D Realms · Restarted repeatedly (finally shipped 2006)
A groundbreaking shooter built around real-time portal technology, so far ahead of its hardware that 3D Realms cycled through designers and scrapped it for years before a wholly new team finally released Prey in 2006.
Announced in 1995, Prey was meant to showcase a revolutionary in-house engine featuring movable "portal" technology — rips in space that could be created, moved and reshaped in real time — alongside heavily destructible environments. Original designer Tom Hall (of id Software and Rise of the Triad fame) laid out early designs before leaving in 1996 to co-found Ion Storm with John Romero. Under successor Paul Schuytema the portal demos wowed crowds at the 1997 and 1998 E3 shows, but the technology proved too unstable to build a full game around, and in October 1998 that iteration was scrapped as its leads departed. Prey became a byword for development hell, restarting in 2001 once portal rendering had become practical; 3D Realms licensed id Tech 4 and handed the project to Human Head Studios, who finally shipped Prey in 2006 — over a decade after its announcement.
Prey’s saga is one of the most cited examples of technology outrunning its era. The portal concept — seamless, movable holes in space you could shoot or walk through — was genuinely visionary, but the PCs of the mid-1990s could not render it reliably, and 3D Realms lacked the discipline to scope the game around what was actually achievable. Designers came and went, demos dazzled and then collapsed under their own ambition, and the project stalled repeatedly.
By the time a stable version finally shipped in 2006, portal mechanics were no longer novel — Valve’s Portal would arrive a year later and define the idea in the public mind. Prey’s long limbo sits alongside stablemate Duke Nukem Forever as a monument to how open-ended development and a refusal to ship can consume a promising game for a decade. That a finished, well-reviewed Prey eventually emerged makes it a rare development-hell story with a genuine ending.