Gunman Chronicles is a futuristic first-person shooter computer game using the Half-Life game engine. It was originally planned as a total conversion for Quake; it then switched games to Quake II, followed by another switch to Half-Life, before being spotted by Valve Software and released as a stand-alone retail product in 2000.
Official game intro video for Gunman Chronicles, which you could have missed even if you played the game already, because Steam Half-Life have some problems with video playback. Converted with a good quality from initial BIK format (only playable directly from the original game version). It shows a piece of backstory of main game characters, so enjoy.
Gunman needs a remaster, remake, and sequels