Hellbound: A 90's First Person Shooter

https://www.kickstarter.com/projects/tobiasrusjan/hellbound-a-90s-first-person-shooter-made-20-years
Steam has the demo. It was fun.

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valveā€™s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.