Mailing the story:

Ravenfield is a single-player 3D shooting game available on itch.io and steam. The game is still in beta so it looks like a "prototype" i.e., not complete, still yet it's completely playable and fun at the same time. I've tried the game and discovered it to be more enjoyable than Red Eclipse or Open Arena, mainly due to the reason that Ravenfield game physic is realistic and comes equipped with many interactable objects.