Marathon Trilogy/WMG

The events of Marathon is all a dream.
That's why Infinity's chapters are titled Despair, Rage, and Envy, and the final level being Aye Mak Sicur.

Infinity's ending shown the Security Officer's acceptance
Mixing this in with Durandal's optimistic ideals of humanity, all the torn bone and flesh hosted by machine were Dissected, and all that was left are strands of artificial muscle and skin tissue still necessary. The apparent disfigurement in his fingers are damage from an explosion.