Lightscape (formerly known as Alphatius) is a free-to-play multiplayer game built in the Doom engine. It uses a modified source port known as Q-Zandronum to create a unique arena shooter experience. Inspired by a blend of modern games like Call of Duty and Halo, and old-school shooters like Quake 3 Arena and Unreal Tournament, it aims to bring Arena FPS to the present day.

More information can be found on the Doomworld post