I haven't had a chance to try the XNA yet, Leadworks sounds awesome so far, yet they lack a demo at the moment.
I'll try out XNA tomorrow morning. Shiva doesn't quite look like what I'm looking for, but then again I can't there's no work that resembles what I'm doing.
@disciple: Yeah I know. lol there's wasn't this many options when we started the project. Take a look at the Leadworks feature list when you can. I know you have used Newton in the past. Oh and I updated the website heavily, a nice list of guns for you,
Trail of Blood site