Half-Life is a First Person Shooter game that was released on the PC and the PS2. There was a Dreamcast version that was planned, but scrapped. The goldsrc engine (the one the original game uses) was built from the Quake engine.
The gameplay is like most First Person Shooters at the time, although it introduced some new stuff as well.
Dreamcast Version Edit
There was a Dreamcast version that was being developed and planned to be released in September 2000. Despite it being canceled, there was a leaked version released. The leaked version had some level differences from the PC version (i.e: Office complex has the elevator explode and adds a little more distance from the elevator with the room where the power switch is), the enemies take less shots to kill, and the power-ups are tweaked to give more. Other notable things about this version is that it also includes Blue Shift (which later became its own game on PC) and it was the first version of Half-life to use the HD graphics pack.
PlayStation 2 Version Edit
There was also a version on the PS2, which was very much like the PC version with some differences.
Half-Life: Source Edit
There is a version of Half-life known as Half-Life Source. The game features changes such as some scientist behaviours being changed. It also features improved lighting and more realistic water, while still using textures from the original game (and the non-HD models). The game was criticized for lack of differences in graphics from the original game. Like with Half-Life 2, the multiplayer is a separate game.
Black Mesa Edit
Black Mesa is a fan remake of the original game. Featuring Half-life 2 graphics and some macinics from Half Life 2. The game lacks the Xen chapter, although the developers state "Xen is under development".