X-COM: Terror from the Deep

UFO: Enemy Unknown arrived in 1993 as the work of Julian Gollop and his brother Nick at Mythos Games, a design that combined turn-based tactical combat with strategic base management in ways that had not been attempted at that scale before. MicroProse, which had published the game under the title X-COM: UFO Defense for the North American market, recognised immediately that a sequel was commercially necessary. Their initial request was direct: they wanted a follow-up within six months. Mythos declined, stating that a six-month window would produce nothing more than the same game with different graphics. Gollop’s team instead began work on X-COM: Apocalypse, a more ambitious design that would eventually be released in 1997. MicroProse, unwilling to wait, licensed the UFO Defence codebase from Mythos and assigned their own internal UK studio to build a sequel using it. Terror from the Deep was finished in under a year.

MicroProse artist Terry Greer described the brief plainly: keep changes to the absolute minimum, reskin the graphics, create a new story, and let the schedule be driven entirely by asset creation rather than technology. The result, released on 1 June 1995, was structurally almost identical to its predecessor. The GeoScape view, the base management layer, the turn-based Battlescape, the research and development loop, the time unit system governing individual soldier actions, the funding model built around satisfying an international council of governments, all of it carried over from the Gollop brothers’ design without fundamental alteration. The changes were environmental. The surface conflict of UFO Defence was submerged beneath the ocean, and a new set of aliens, equipment, and mission maps was built around that premise.

The setting worked for reasons that went beyond novelty. The story placed the action forty years after UFO Defence, positing that the destruction of the alien command structure on Cydonia had left a transmitter active on Mars that reawakened a second alien force dormant beneath the Earth’s seas for millions of years. The narrative conceit resolved a practical design problem neatly: all technology from the first game was unusable in salt water, which meant players could not carry their UFO Defence knowledge of late-game weapons directly into the new campaign. Equipment had to be researched and developed from the beginning, from primitive underwater weapons toward more sophisticated captured alien technology. The alien designs drew heavily from the fiction of H.P. Lovecraft, with creatures such as the Lobsterman and the Deep One giving the game an atmosphere of oceanic horror that separated it clearly from the UFO Defence aesthetic. The final mission location, T’leth, was a direct reference to Lovecraft’s R’lyeh.

The difficulty proved to be the game’s most discussed characteristic, and the way it came about was not straightforwardly intentional. Players had complained in the aftermath of UFO Defence that the game was too easy, which MicroProse took as an instruction to raise the challenge in the sequel. What MicroProse did not know when they received that feedback was that UFO Defence had shipped with a bug that caused the game to silently revert to Beginner difficulty mode during play. The complaints of ease were complaints about a defective product, not about the underlying design. Terror from the Deep was calibrated against a difficulty level that had never been what players experienced. The consequence was a sequel that pushed beyond what the engine and the core design could comfortably support, with enemy health values, particularly on the Lobsterman, requiring levels of ammunition expenditure that the resupply economy made difficult to sustain, and mission maps, especially the large vessel assault missions, extended to lengths that Jake Solomon, who would later lead the 2012 XCOM reboot, described as four times longer than any human could realistically make. Julian Gollop himself criticised MicroProse for making the difficulty too tough and the levels too big, long, and tedious.

The two-part missions, which required players to fight through sequential tactical maps without the ability to resupply between them, were the mechanic that crystallised these tensions most sharply. Running short of ammunition or losing experienced soldiers in the first half of a paired mission carried consequences directly into the second, with no opportunity to compensate. The structure was not inherently flawed as a concept, but combined with the other difficulty factors it produced situations where failure felt less like the consequence of poor decision-making and more like an attrition of resources that no reasonable planning could have prevented.

Reception was strong regardless. The average review rating across approximately fifty magazine reviews at the time of release fell between four and five stars. PC Gamer called it a great sequel and a superb game in its own right. GameSpot summarised the prevailing critical position concisely: it was exactly the same game as UFO Defence, only much more difficult. The fan-developed OpenXCOM project, which began as a modernised implementation of UFO Defence, extended its scope to include Terror from the Deep support, correcting bugs and improving the AI in ways the original release had not managed. The game’s Steam user reviews currently sit at 92 percent positive. Thirty years on, it remains the entry in the series that players are most likely to describe as unfinished business.