I was lucky enough (or unlucky, according to how things ended. . . ) to be a spectator to a 40-years war between two neighbouring NPRs a couple of months ago. I knew very little about them until I sent a specialized spy ship to gather some information. One of the two species was apparently getting the upper hand, had been expanding to two adjacent systems while their opponents were relegated to their own system, since the only other direction they had was guarded by five of my jump point defense bases (twin ultraviolet 20cm turrets on all of them. ) The weaker NPR's home system was littered with wrecks, ranging from 5000 to 30000 tons. The stronger NPR employed faster (MP era) beam weapons, while the defending weaker NPR (Ion drives era) had missile ships. Eventually I went in with a scout ship and sent probes all over the systems. The enemy NPR had a 20+ strong fleet orbiting the other NPR's planet, they were clearly bombarding or invading it - and the shipyards weren't there anymore. Sadly I had to abandon the game because I had horrible luck with mineral placement, but it was really interesting to see two NPRs face each other in an all-out war like that. There were also relatively little interruptions in the game subpulses, considering the amount of wreckage! Wish I had taken screenshots of that.