Awesome.

I think an urban landscape would be a cool setting. I'll let you fill in the details. =)

As for conditions...

Weapons:
All I want is a Katana to start with.

It would be preferable if we didn't have guns at start. However, there might be a gun/pawn shop somewhere nearby, if you know what I mean.

Also, to make things interesting, no killing civilians.

That's really all I had in mind.