More games like Heretic 2, Turok 3, and Deus Ex

 System Shock 2 - This sci-fi horror game has a similar immersive atmosphere and RPG elements to Deus Ex.

Blood - Developed by the same company as Heretic, this first-person shooter has similar gameplay and atmosphere.

Unreal - This classic shooter has a similar blend of action and exploration as Heretic 2 and Turok 3.

Thief: The Dark Project - This stealth game has a similar focus on exploration and careful planning as Deus Ex.

Kingpin: Life of Crime - This first-person shooter has a similar gritty atmosphere and violent gameplay to Deus Ex.

Shadow Warrior - This classic shooter has a similar emphasis on fast-paced action and humor as Turok 3.

No One Lives Forever - This spy-themed first-person shooter has a similar focus on exploration and storytelling as Deus Ex.

Hexen - Developed by the same company as Heretic, this first-person shooter has a similar medieval-fantasy setting and gameplay.

Red Faction - This first-person shooter has a similar emphasis on environmental destruction and exploration as Turok 3.

S.T.A.L.K.E.R.: Shadow of Chernobyl - This post-apocalyptic shooter has a similar focus on exploration and survival as Deus Ex.