zdoom/gzdoom are really full-featured 3D engines now. They can scale down to play original Doom content, but they also support full 3D models, colored lighting

zdoom/gzdoom are really full-featured 3D engines now. They can scale down to play original Doom content, but they also support full 3D models, colored lighting, sloped surfaces, and even room over room. The reason to use a doom engine like this is that level creation is still a 2D draw out each sector task, which is a lot simpler and easier to pick up vs. modern engine's fully immersive 3D modeled level creation.