: Just so that I am clear: Aleph One + M1A1 allows me to play Marathon 1
: (enhanced, upgraded)
: Aleph One + now-free Marathon Infinity files allows me to play Marathon
: Infinity
: Aleph One + now-free Marathon 2 files allows me to play Marathon 2
That's right. Aleph One is the open-source updated version of the Marathon 2 engine. Marathon Infinity uses the same engine as Marathon 2, so Marathon 2 and Marathon Infinity Map, Shapes, Images, etc files all work with AO. You may need the file-typing scripts from http://source.bungie.org for them to work properly with AO, as well.
- Reiginko