- I recommend the [dhewm3](https://dhewm3.org) source port. If you don't want to compile the executable yourself, you can [click here](https://github.com/dhewm/dhewm3/releases) to download dhewm3's pre-compiled binaries.
- Its codebase is [nice and tidy](https://fabiensanglard.net/doom3)
- I've been using the [idTech game engines](https://en.wikipedia.org/wiki/Id_Tech) for various projects, such as [Quadrilateral Cowboy](http://blendogames.com/qc) (idTech4) and [Thirty Flights of Loving](http://blendogames.com/thirtyflightsofloving) (idTech2).
This package is licensed under the zlib license. Read the license details here: [LICENSE.md](https://github.com/blendogames/doom3-starter-kit/blob/master/license.md)