Between Firearms and Firearms: Source there was Firearms 2. This was one of at least two attempts at a Firearms reboot.
Between Firearms and Firearms: Source was Firearms 2. This project was one of at least 2 attempts at a Firearms reboot on the Source Engine. Development of Firearms 2 halted and I eventually joined up with the Firearms: Source team to complete that project.
I was the only programmer on the project, therefore I was responsible for everything related to the code. I even created a few assets myself when I needed them. I was responsible for creating the weapon behaviors, animation state machines, gameplay rules, HUD, UI, and effects.