The following are my first impressions I had with the game:
The opening of the game was pretty cool with the company logos of HVS and SEGA.
At the menu screen, I really liked the music. It was a really cool, kinda hip-hop-ish and totally awesome.
Controls are great. They feel really comfortable as I can aim and turn the camera with the IR. I setup the controls to be more of my liking, similar to the controls of RedSteel and Medal of Honor: Vanguard. They can even be customized so that the control stick turns the camera.
The story is good, especially for a FPS. Starts out with a flashforward to around the middle of the game and then it really starts from the beginning. I really liked it, it was almost like Agent Smith meets National Treasure in that it's got surprises and plenty of conspiracies. The ending was a bit disappointing, but it ends in a way that you KNOW there's gonna be a sequel.
The sound effects for weapons aren't exactly too great. Alien weapons sound good, but human weapons like the Shotgun and SCAR sound like they're a bit muffled.
The game even has achievements for completing missions, killing a certain number of a certain type of enemy and ones for killing a certain amount of enemies with a certain weapon. Gonna play through it with the cheat that causes 1 hit kills in order to rack up those achievements none of you will be able to see. :/
Overall, the game is great. I really enjoyed it. Haven't tried Multiplayer yet though, but plan to soon.