Hexen II
Raven's own Win32 source as released in 2000: glh2.exe on WGL, its OpenGL drawn through WebGL.
Hexen II runs on PRISM, a C and C++ compiler written in plain JavaScript. ★ Star it on GitHub if you liked seeing it here.
Arguments
PRISM's log
What PRISM says while it runs the program shows here once it is playing.
⚠️ Licence
Raven's own 2000 source release holds the GPL (gnu.txt) and also an Activision source-code EULA, with no licence in the files themselves. Its build is offered here under the GPL, as Debian and the source ports have done since; no Hexen II data is. If you hold rights to it and object, open an issue at github.com/jfrelat-lab/prism/issues and the build comes down.
Source
archive.org / details/hexen2-masterthe program
website
jfrelat-lab / prismthe compiler
GitHub★ Star