I've been playing it pretty much all day now. To put it simple, I'm impressed.
I'm playing it with a controller that I picked up a while back at bb for $24. The controller is identical to a ps2 controller. It fits perfectly with this game. The only change I made to the controls was invert the 'look' axis. All other buttons where right in place.
I didn't even try using mouse/keyboard. Normally I prefer games with mouse/keyboard... but this game gave me an itch to plug my controller in.
The gameplay is pretty intense. And it's not all just shooting the laser. You have to switch to your 'hold' beam and throw your trap out on the floor and wrestle with the ghosts to get them to the trap. There are also 4 different weapons which you purchase and each weapon has a secondary fire mode. You have all weapons equipped simultaniously. You have to scan the ghosts to find their vulnerabilities so that you know which weapon to use, and each weapon is totally unique.
The graphics are pretty nice. But the sound is the true highlight. All of the music and effects are perfect.
I'm playing using:
Core 2 Duo @ 3.0ghz. (not quad)
Geforce 8600gt
2gigs of ram
The framerate is slightly low, but it stays smooth so I rarely notice anything. If I was to take a guess I would say my framerate stays between 24-45. But it NEVER drops to a crawl so I'm satisfied.
The game has been a blast so far. I do wish that it had some type of quick-mission mode so I could just go into some randomly generated area and bust stuff up. (multiplayer like this would be pretty fun probably)
I forgot to mention, the physics are nice.. I would say that it's similar to half life 2.. you can grab onto stuff with your tractor beam gun thing and move things around similar to the gravity gun in hl2.
And the story, in my opinion, is movie-quality. I kind of get the feeling that this was actually intended to be a movie but they had to settle on a game instead.
EDIT: Woa, holy crap! I just found an 'artifact'.. when I scan it it says 'a treasure from the future'.. the artifact is called 'ghostbusters movie'.
A new movie in the future?