Unfortunately the final release hasn’t inspired as much as it would have done nearly a decade ago. What was once cutting-edge graphically is now a pretty but pretty-samey Doom3-powered affair, and the fabled technology has become linear through scripting as opposed to a freeform approach attached to the end of a weapon. Perhaps most unfortunate, at least for the development team, is that the trailer for Valve’s Portal was made available at around the same time as Prey’s release, which looks much more akin to 3D Realms' original space-time-breaking concept.

And it starts so brilliantly too – a heavily scripted but well-directed intro sees hero Tommy abducted by a giant UFO and carted around its mechanical belly until the ‘inevitable thing that goes wrong’ and the game starts proper. For the first hour the game confidently throws the player along a fantastic gravity-defying, space-bending, proportion-shifting ride. Witness Tommy standing on the side of a wall, peering through a portal spawned in midair and finding a whole new area contained within. You can walk around the portal, making it visible from one side only and indeed step through to enter the new area. Slowly however, the flow of inspired level design starts to dry up. Portals continue to seemingly randomly appear and the journey continues on every conceivable axis, but the experience becomes predictable. Though occasionally used to brilliant effect, all too often the Portals are an excuse to spawn an enemy behind the player, or up there, on the floor to your left.

Credit to the level designers though, despite endless gravity shifting and impossible architecture, the game is never confusing or unworkable. Walkways climb up walls and double back across ceilings, and occasionally switches can be used to shift the gravity entirely. It’s refreshing to see a First-Person Shooter use 3D space so elegantly; indeed, this has to be the most creative use in the genre since Alien Vs. Predator. Adding to this, a skill Tommy learns is the ability to “Spirit Walk” – an out-of-body experience that gives you access to otherwise impossible platforms adding an extra edge to the well-designed puzzles. Though many such puzzles may be generic with their reliance on switches, it is pleasing to see entire rooms flip around with the shifting gravity, or find yourself in an endless loop of portals until the solution is cracked.

The main faults of Prey do not come from level design, rather the mechanics underpinning the whole experience. The energy system is tragically counter-productive, essentially removing all atmosphere and challenge. Whenever Tommy runs out of health, a short (poor) minigame is played for a few seconds before he is plonked right back onto the same spot. There is no Game Over. Since the game is basically played in God Mode, the result creates a gung-ho mentality with zero consequence. A further damning fault lies with the weaponry, none of which satisfies and it is disappointing to find Human Head falling into the same trap that so many have done of not adding oomph to their alien creations. They all fizzle, splut and spit, but none boom, sizzle and shake. With the AI showing little to convince and less to motivate, by the end of the six-hour experience Prey seems to run on auto-pilot, waking from the trance only to reveal a handful of truly wonderful examples of epic level design.

Prey is an experience worth applying for, and though it isn’t exactly great value for money at six hours long (and the multiplayer, known as "MultiPrey", features just Deathmatch and Team Deathmatch), there are a few sights worth seeing, and the plot is a fraction more interesting than the Save The Earth, Save The Girl setup. Monotonous it can be, but it’s rarely frustrating or difficult to play. That said, if it was released in 1998 it could have been genre-defining, in 2006 it is merely genre-filling.