Portals, Antigravity, and a seperate spirit mode adds great value to the gameplay and puzzles with in it. Great Fun!
Graphics/Physics: 9 - Fantastic graphics, very much like Doom 3 in style or gore. Graphics alone could make this game interesting enough for some time. Great physics envolved with the portals, spirit mode, and antigravity.
Sound: 7 - Sound quality is great and has realisitic value to the voices. Aliens being able to speak english is rather lame
Environment/Maps: 8 - Maps are a little over dark or shadowed but is fine due to the context of the game. Very detailed maps, great use of the antigravity and the spirit mode adds a lot to the gameplay.
Game Engine/Scripting: 8.5 - Great physics envolved with the portals, spirit mode, and antigravity, very top notch. Engine was made very well, and quite similar to Doom 3. A few minor issues with the menu.
Interface: 8 - Menu was buggy and even at times unresponsive or so it seemed. User interface during gameplay was very well made. Interesting selection and use of weapons in both normal and spirit modes.
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Overall: 8.5 - Portals, Antigravity, and even a seperate spirit mode adds great value to the gameplay and puzzles with in it. Story gets a little weak at times but graphics and style make up for it. Games style is very close to that of Doom 3, by that I mean the gore, use of shading, and environment.