Is it possible to play on this game with LAN connection only? We tried to play on this with two laptops at my workplace when there was problem with the modem and we had free time due to the problem.

We haven't seen each other in the game's multiplayer. I've used this GOG version while he has the Steam version. Does this game requires net for multiplayer, and there is no option for simple LAN?

I never bought this game because there were never clear answers to this.

The metaserver is required for seeing games even on the same LAN. It also checks authentication keys, so that if you have the same, it won't work. Direct IP option present in DEFCON is removed. The packets are encrypted to make reverse engineering more difficult, and this code is removed from the public version of Multiwinia source code (which is incompatible with the official binary version).

Enjoy DRM-free as defined by GOG.com!