This game feels more like a tech demo with a lot of content. It's worth a look, just for some of the technology.
Gameplay feels curiously like Quake 4, with fewer enemies and less danger. Graphically, they could have lifted most, if not all of the textures of Doom 3 or Quake 4 and planted them within this game. The untrained eye would likely not have noticed; you'll get a sense of Deja Vu stomping through the corridors with your lighter (a 'flashlight', that makes a source of low flickering light at your location until it overheats). In other words, the graphics have a very familiar feel to them. At one point, even your character mentions this in a joke-- "Wow, it's so dark in here. I'm DooMed." The redeeming trait with them is that the graphics are used in some interesting and different ways, and glass/forcefield effects seem to have had special attention. An interesting perk I discovered is that the enemies can use the medkits strewn about if they are injured, and they do have an effect.
Weapon wise, the primary rifle acts a great deal like Quake 4's rifle. The main fire mode is a rapid fire shot that has little recoil. The secondary fire brings up a scope, which fires a more powerful (but more ammo inefficient) shot. Sound familiar? The same can be said of the other weapons, in that they feel like guns from other games. The 'auto-cannon' is a chaingun/grendade launcher, and the acid sprayer acts suspiciously like the Flak Cannon of UT fame. The leech gun was a neat idea that was not realized fully; different forms of energy result in different shots from the gun. They might as well just have added the 3 other guns for the types of energy it used- one is a red, burning energy which fires like any SMG, one is a Freeze energy which is simply a flamethrower in reverse (the freezethrower from Duke Nukem fame), and another is (again) UT's lightning gun.
The Ai-- though it claims to be adaptive- is hardly a challenge. Simple peek-a-boo tactics you've used in other games will work perfectly well here, if not better-- if on the off chance a grenade does manage to get you, you won't die. You'll be put into a state of 'undeath,' much like what you would see in the old adventure game Soul Reaver. After a few seconds of target practice on the manta-ray like demons, you'll be back in the saddle, and depending on what amount you killed of what color (blue mantas give you spirit energy for spirit walking, and red mantas will dictate how much HP you revive with) you might actually be in a BETTER position than when you started. This is true even of bottomless pits or in the event of your characters complete disintegration. In the event that either of those unsavory events happens, you'll be put at the door to the room as opposed to where your body fell, only all the enemies you killed in that room will already be dead.
Puzzles aren't difficult, either. Much of it involves the gravity switching. A lot of the enemies tricks involve using the gravity as well; you will get used to these tricks by the second or third time they happen. Shooting someone on the ceiling isn't a bad effect, but a lot more could have been done with the gravity, and it's a shame it wasn't pushed further. Some neat puzzles involve the portal tech; in one scene you encounter a 'hall of mirrors' effect. The plus side is it's cool; the down side is that the portal in front of you puts you behind the enemies aiming to the corner you are hiding behind, allow you to dispatch them without any problems (you're in such a position that you can see them, and shoot them, but they cannot fire back as it's a one-way portal.) and then just blaze through the area after about 10 seconds of getting your bearings.
Multiprey (the name for multiplayer mode) is simplistic at best, and has been done better. The game feels rather unbalanced toward specific weapons; the acid sprayer in particular is devastating, as well as the 'rocket launcher'. The acid sprayer can kill in one or two shots at medium range, and doesn't require much aim; it'll simply cover a ten to fifteen foot area with damaging pellets, and fires quick enough to dispatch a freshly spawned player before they realize what's happening. On the plus side you can spirit walk, and the arrows from your spirit bow are rather powerful. It doesn't have much of a point though, and is more detrimental in most situations. Your body- the thing that gives other players points- is stationary and unprotected, and in the middle of a deathmatch that's an almost laughable mistake on the players part. Killing someone with the spirit bow is akin to getting a kill with shock paddles as a medic, or a knife. It'll get a quick chuckle, but is there more as a placeholder.
The game is more like an open invitation to modders as opposed to a genre bending, mind-blowing piece of video game history. It's like Turok stole Raziel's powers, and is fighting the Strogg inside a giant space-ship that Serious Sam ran through once before. It's as if the developers were trying to collect a great deal of aspects they enjoyed from other games, into something that could be used in the future by other people. All in all it feels like a tech demo with a lot of content. Though, one has to wonder-- if that really is the case, then what might the mod-making players have in store?