A modified multiplayer only version of Tribes: Vengeance. It is patched to 1.01 and does not require the CD to be present to play.
How to get a CD Key:
Go here: http://www.bramkaproxy.com/ (This is a Polish proxy)
Enter this in the proxy: http://www.cdaction.pl/seriale/Tribes_Zemsta
It's a Polish only website, so that's why we need the Polish proxy.
Enter you email address, and you should receive an email with a CD Key.
Go to your Tribes ReVengeance install folder and find tvkeychanger.exe
Double click it, insert the cd key you recieved and then you're good to go.
