Yea this was all 360 players. It's a pretty bad PC port to be honest, I think it's actually an emulation of the 360 game because some of the game mechanics break above 30 FPS. It was also designed for cross-platform play with M+KB and Controllers in the same game. They made some pretty obnoxious tweaks to M+KB controls to make it fair, so if you are flicking your mouse around very quickly you will have decreased accuracy. For M+KB players, this is blasphemous, handicapping one of the inherent benefits of the Mouse.
If there was a re-release, it should be PC only on Steam with none of the nonsense that was done to M+KB controls to balance for controllers. It should also be designed to run at 60 FPS.
Tied to Windows Vista, back when PC gamers had to pay for online with GFWL, overpriced, and a bad PC port that intentionally handicapped PC players so MS could market cross platform play. There is a reason it's a prime example of the failed GFWL experiment.
Underneath all the sludge of shitty business decisions it's a great game though. But, I still consider it a great console shooter and a bad PC port.