Marathons are awesome games still. It’s kinda sad that most of the PC players missed them. If my memory serves me right, only Marathon 2 was publishes on Windows quite late and it got bad reviews because of Quake and its 3d graphics. Marathons had bitmapped NPCs instead of 3d models.

Before Microsoft bought Bungie, They open sourced the Marathon code and gave the game data for free. Luckily people have been working on bunch ports for modern OSes:

https://alephone.lhowon.org/