Apparently you can use contemporary weapons for the age you play in. Whether this means we'll be able to engage Romans with the gladius and pilum I do not know. After having played the demo, which featured the US Civil War, I had to use muskets and six shooters for the majority of the game. Later on I was given a machine gun when the going got tough. Even then the game wasn't as easy, simply because of the large numbers of enemies on screen. Overall though the game isn't bad. It's made by an indpendent games developer and as a result it has some poor production values. Mostly it's let down by some graphical glitches here and there, poor voice acting, and some bad AI. I hope that some of these problems will be ironed out of the game soon. I still like the concept thoug.
I think it would be cool to be able to use a gladius in the game, but it would look a bit odd in first person I would think...