It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

×
^ Topic.
Yes, IIRC.
You can but it's rather unstable, you're better off with the otherwise far less fancy xduke until they get the multiplayer situation sorted out.

(Disclaimer: I may be out of date, it's been a few months since I've tried, but I haven't heard anything to the contrary)