https://www.pcgamer.com/old-school-fps-ion-maiden-has-the-same-engine-as-duke-nukem-3d-shadow-warrior/

Ion Maiden is an old-school shooter made in the same Build engine as Duke Nukem 3D and Shadow Warrior. On the heels of its reveal, publisher 3D Realms and developer Voidpoint launched Ion Maiden on Steam Early Access today. It's $20 ($18 through March 7) and contains a "multi-hour preview campaign." 

Starring Shelly "Bombshell" Harrison, the protagonist of 2016's Bombshell, Ion Maiden is a proudly retro FPS. 3D Realms promises "huge, multi-path levels filled with those famous colorful keycards and plenty of secrets and Easter eggs to discover." Ion Maiden will not feature regenerating health or a cover system, but instead promote classic running and gunning.