Alright, now, admittedly, I'm just sharing this for the novelty.
Marathon was a trilogy of early first person shooters released for the Mac in the mid 90s. Nowadays, you'll know the developers, Bungie, for going on to make Halo and Destiny. To me, though, they'll always be the tiny studio behind Marathon.
After the trilogy was released, Bungie made its comprehensive level editing suite, Forge, available, and I started making my own maps for the game.
One small catch though, I was less than 10 years old at the time.
Yeah. So, it kind of goes without saying not to expect too much in terms of quality level design. Nevertheless, if you're curious to see where I cut my teeth with game making, you can download everything I made below:
How to play these maps:
Download Aleph One alongside the original Marathon games here. I recommend Marathon Infinity for running my maps. Don't worry, it's all open source and free! Aleph One is the engine that enables these games to run on modern computers.
Save my maps somewhere within the same directory as Aleph One.
Launch Aleph One. Click Preferences, Environment, and select a map from the list. The maps with (CAMPAIGN) in the name will loop through consecutive maps, the rest are singular.
Now return to the main menu and click 'Begin new game'
Or, you know, you could just play the original maps...