Marathon World is a small modification of Marathon Infinity on the Aleph One engine.
The aim is to bring Marathon's multiplayer mode up to date and on-par with multiplayer games like Unreal Tournament and Quake 3.
Current list of achievable goals
Design principles for level archetecture will be Marathon/Halo inspired (Seeing as some of Halo 3's maps are just remakes of Marathon maps but with random props placed in the center, you could pretty much say in-door layouts based on Marathon, outdoors based on Halo)
Somewhere in the heavens... they are waiting.