The cases of nailgun ammo carry the logo for "Nine Inch Nails". Nine Inch Nails is the one-man band of the game's composer, Trent Reznor.
Originally intended to be a medieval game with swords and a dragon, but only a few months before it was released guns were added and roleplaying aspects removed. The dragon was also removed, although several other monsters like the Knights and Fiends were kept. The dragon was later added in the second mission pack by Rogue Entertainment.
Could support up to 32 players in multiplayer mode. A record at the time.
Various games used the engine such as, Hexen II, Laser Arena, and Half-Life, which is a heavily modified renamed to GoldSrc, which supported Direct3D, skeletal animation, colored lighting, higher polycount, etc.
One of the games that created 3D engine.