Initial release for MS-DOS, also you can play on other desktop operating systems, if you have an Android phone, you can play this game using QI4A. This is the Quake but with Half-Life SFX. This idea was inspired to this video as Quake Demo Intro but with Half-Life 1 Sound Effects, but you can hear these Character's sounds in other maps, I'm also used a cut character as Stukabat for this Knight, you can meet this sound in E1M2, these Stukabat's sounds was in Half-Life Absolute Zero. In addition you can test Half-Life Alpha maps under MS-DOS.
You should make a video of gameplay sample.