Prydon didn't get a chance to show off a lot of story really. You must be referring to the TDA story
Anyhow, Prydon (I kinda worked on this, am I allowed to list it?) and Nehahra.
Nehahra had those creepy alien-things, whatever they were, armed with SNG's and Sprocketlaunchers IIRC. Those and the original AvP aliens are the most scary FPS monsters I've seen to date. Unpredictable hiding- and peek-a-boo behavior, and creepy voices. Awesome. Also, when you shot a monster with a Sprocket, they came running towards you, attempting to catch you in the blast. Also awesome. Scrags gave me quite a scare when they did this, as they were so incredibly effective at it.
Prydon cause it's a good hack-n-slash. Gotta love those.
I do have some fond memories of Team Fortress with some friends over LAN. Playing it online is just scary.
An Airquake wannabe called podquake was also fun over LAN. I had not heard of Airquake, so podquake was awesome to me. It's essentially the same, except with starwars ep1 podracers for models, and plasmaguns. Strange thing that those podracers flew like aircraft, but we didn't mind, it was a blast. I even made maps for it.