Prey

The Good
This game reminded me a lot of Half Life. It's a very linear FPS (which isn't necessarily bad, if done right), and it's chock full of scripted sequences and events, and has a unique setting with some innovative gameplay mechanics.

The most important change to the standard FPS gameplay is the fact that, early on in the game, you get the ability to "Spirit Walk". This lets you walk through force fields, as well as interact with some ethereal parts of the landscapes, such as invisible "spirit bridges". As a side effect of gaining this ability, your character never actually dies. Once you run out of health, you're transported to the Spirit Realm, where you spend a few seconds trying to shoot down red and blue spirits before you're yanked back into the world of the living. The more red and blue spirits you shoot down, the more hit points and spirit points you come back with.

This eliminates the tedious quicksave/quickload method of playing most other FPS games - dying's no longer an issue, so you can have as many tries as you like to get past a tough spot or a Boss monster. Unless you fall off a cliff, you'll reappear exactly where you were before, and you can continue chipping away at that big monster. (Falling off a cliff will redeposit you back at the point right before you fell).

Even without that feature, the game would still be a lot of fun to play. The environments are heavily detailed, and they look extremely realistic. Some of the environments are huge, which came as a bit of a surprise to me. This game was built on a modified version of the Doom 3 engine - since Doom 3 was so closed-in and claustrophobic, I never would have guessed that the engine could handle such huge, wide-open areas in Prey.

Another big gimmick in this game is gravity manipulation. Since dying isn't an issue with the Spirit Walk ability, it's not challenging if the game simply throws waves of monsters at you. There are a large number of logic puzzles in the game, many of which require you to come to terms with the artificial gravity in the environment. In many areas, you'll begin to lose all concept of "up" and "down" as you stand on the ceiling, shooting aliens who are standing on the walls and the floor (or from your perspective, the "ceiling"). In many areas, you can also manipulate the gravity by flipping a switch, and suddenly a wall becomes the floor, and this mechanic is heavily used for many of the game's puzzles. At one point late in the game, your character flips a switch causing the floor to become the ceiling, which you've done a hundred times already by that point - upon landing on the floor, he remarks "Oof. I don't think I'll ever get used to this." I can certainly see that - no matter how many gravity-puzzles I go through, there's still a part of my mind that insists that "up is always up, down is always down", and this game throws that concept out the airlock.

The portals were a nice touch, too. There are a number of them, leading to different areas. As you approach a portal, you can see into the environment it leads to. Stepping through one is completely seamless - in fact, firing into one will harm monsters on the other side. In some cases, there are small "portal loops", where entering a portal will make you appear behind yourself. It's a bit of a shock to look through a portal and see yourself, entering a portal.... The portals seem like such a simple concept on paper, barely worth mentioning - but Prey pulled it off very well.

The Bad
Well, it was awfully short. I beat it in less than two days. The "never actually dying" thing is great, but it definitely seems to shorten the time it takes to complete the game.

Also, all the gravity flipping gave me a sense of mild vertigo after a while. Wasn't too bad for me, but I could imagine that it might be problematic for some people.

The Bottom Line
I'd describe this game as "TOTALLY AWESOME!! .... But way too short."

I don't believe I'd recommend paying full price for it; $50 is a bit much for a game that won't even provide a solid weekend of entertainment. It was a real blast to play, but it was over far too soon.