Designers: Marc Ellis, Koumei Satou, among others Released: October 2001
This is an interesting one. Ellis wanted to make an interesting concept for HL. So he employs the help of Koumei Satou, a Japanese Half-Life mapper who previously made Peaces Like Us. It's weird, because first-person shooters are a minority in Japan, compared to its frequency in the US and Europe.
Anyway, you play as Gordon McGinley, and like most other mods, all hell breaks loose. But it's a slight alternate perspective, done in a different place, style and pacing. It has a few branching paths, and the maps get weirder in some points. All a distinct style of Satou's work.
K.S. later made Mistake of Pythagoras, a HL2 modification that kept the same eccentric nature of his HL1 efforts.
This covers the "training area," simply a level that shows the events that happen later in the mod.
NOTE: THIS MOD WILL ONLY WORK IN HALF-LIFE. THIS WILL NOT WORK IN HALF-LIFE: SOURCE, DO NOT ASK.