What's the difference between normal, Darkstar, and uplink versions?

[Samuel Stone #f2plivesmatter]

I didn't find anything about them in the FAQ section

[Quazzar]

Normal is the main game.
Darkstar is a very old (but good) mod that was distributed by PC gamer I believe.
Uplink is the Half Life 1 demo, which is basically a short campaign with maps not included in the base game.

[Taehl]

A little extra context:

Darkstar was one of the first, if not the very first major mod released for HL1. Most people hadn't ever heard about mods back then, but PC Gamer magazine helped promote Darkstar (as well as a mod called They Hunger) by including them on one of their demo disks. Darkstar includes a few PC Gamer references in turn. Maybe not amazing maps by modern standards, but it inspired so many more people to start making mods, leading to kind of a golden age of modding and firmly cementing HL1 in videogame history. Many of those mods were lost to time when FilePlanet closed down, RIP.

Uplink started out as a section of levels you'd go through before Lambda Core, but it was cut before release. After release, Valve took those maps, polished them, and made them into the game's demo. IMHO It ended up being more detailed and full of interactive stuff than the actual campaign! Short, but sweet. My advice: Break the soda machine.