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.
Gunman Chronicles is basically the ultimate loveletter to Goldsource and the Half-Life creation scene. Just like other classics like Day of Defeat or Counter Strike it started out as a humble modification and blossomed into a full fledged release.
What makes Gunman so notable is just how big and ambitious it feels, I never really felt like I was playing a modification turned into small budget game. I really felt instead like I was playing the end of an era in terms of Half-Life. The maps are richly detailed with cool interactive elements, lots of enemies ranging from alien lifeforms, human soldiers and rampant AI, a ton of visual variety of both entire landscapes and smaller zones within an area. Honestly I was impressed with what they pushed with the engine in terms of how big and how varied everything felt, it really pulls off a sense of scale in terms of its outdoor environments that I don't see in other Goldsource games or modifications, which is honestly a testament to the developers' skill of world/level crafting.
The gunplay is solid, just as anyone should expect from a Goldsource based game with frantic action that rewards various playstyles from the cover based shooter to the jumpy quaker. But what really elevates it is the incredible depth of its weapon system. You can finetune your weapons to perform in a number of roles, the shotgun can be modified to work like a slugbased rifle or a multi-shot crowd control killer! But just when you think it couldn't get any cooler, you have the ability to operate tanks and for an engine so old, they honestly perform beautifully, giving an awesome spice to an already solid FPS experience.
You take some of the best this engine can offer, give it incredibly satisfying and solid gameplay with amazing weapon customization and the ability to drive vehicles and then tie it all together in a compelling highly cinematic story set in a unique universe that can best be described as "proto-firefly" and you got one hell of a game.
My only complaint is that Gunman has sadly been forgotten.