The first game I played over the internet (kinda) was the Microsoft flight shooter "Hellbender" I connected with a friend of mines by dialing directly over the phone line. We had a hell of a time getting it working though :lol:. The first game that I played over an organized Internet system is the original Diablo. Followed by Diablo 2 or Half-life, I forgot which came first. But in terms of online playing time, Half-life by far.
I wasted years blowing through at least 20+ different Half-life 1 mods: Battle of the Milinium, Rocket Crowbar, Action HL, Existence mod, Dragonmodz, TFC, CS, Day of Defeat, Bumpercars, Natural Selection, Wizard Wars, Svencoop, "Pirates Vikings, and Knights", Richochet, Gladiator, Vampire Slayers, the Specialist, Judgement, Worms HL, Opposing Forces, Jailbreak, Science and Industry, Snark Wars, The Wastes, Holy Wars, Train Hunters, Braindead, The Battlegrounds (revolutionary war mod), The Opera, Firearms, Global Warfare, Master Sword, Goldeneye, Scientist Hunt

, Runaway Train, and I'm sure others. There was much fun to be had for that initial 20 dollar purchase of the game from my local, independent used game seller back in 1999.