Good times.
I don't remember too much of what I did, but I made a couple of maps one of which was hosted on a server for a week or something. It wasn't especially good, but it was a pretty amazing experience that somebody else thought something I made was good enough to try out, and that I could log into a "real" server and see it in action :P
I'm sure this game shares some DNA or history, but man, big nostalgia hit.
About 20 years ago we used to play BZFlag in the office during lunch, maybe 6-8 of us in a company of ~50. Someone complained that we were using up the network bandwidth, although I knew the BW for the game was tiny. I bought a bunch of USB Wi-Fi adapters from Woot! and we would place them on the tops of the cubicle walls when we played. We wouldn't actually plug them in. We played on and off for several more years without any network complaints. I even built a map of the office, taking pics to use as textures, so we could drive tanks around the office, jump on our desks and shoot each other.
BZFlag suffers from inbreeding, where a couple of abusive admins can harass and ban players across all the (two) popular servers and choke off an already-small community. They abet cheaters and ban those who call them out, which is perplexing and sad.
This and titles like it made my childhood
The Apocalypse map is still golden!
(At least I remember reading a discussion on BZFlag licensing a decade ago, when his inactivity was already noted. Looking at the commit log, he made 9 commits since 2011 and they mostly concern licensing.)