The last level is a pure work of art. The level's detail is immense and it has a lot of storeys overlapping each other.
A three level (plus one intro level) mini-scenario for Marathon Infinity.
This scenario is a sequel to Marathon Phoenix, although it is not as difficult. The player is reunited with Durandal, and the two follow the path of the UESC Atreides to a distant Human base.
EDIT 2/11/2014 You will probably need the Previous AI plugin to make this work! http://simplici7y.com/items/aleph-one-previous-ai