Firearms: Source is a semi-realistic arcade shooter with smooth gameplay designed for maximum enjoyment by the player. There are no respawn times, but the weapons are modeled accurately and function differently from one another. This release features 33 weapons and 8 maps and several patches have been issued since release on July 23. The developers have also promised additional content including maps and weapons that is due for arrival in August. More information can be found on the press release, ModDB page, or Podcast 17 interview.
You can download the mod here, along with patch one and two.