I played Signal Ops multiplayer with a friend yesterday and we had a lot of fun. The game is tricky to figure out at first (as with any novel game concept, I’ll bet) but once you get the hang of it, it’s a really fun game.
One thing that we noticed is that if two people happen to take control of the same screen (usually by accident), the movement of the associated character becomes locked-up and very jittery. Perhaps it might be possible to restrict this, so that only one person can take control of a screen at a time?
Also, when exiting or entering manholes, the camera occasionally glitches through the ground. It’s not a huge issue (mainly cosmetic), I just thought I’d point it out in case you guys weren’t aware of this.
Oh, and one small suggestion: it was not obvious which port to forward at first until I searched the web and found it in the Steam forums. It might be an idea to put this information in the network menu itself.