LAST MISSION PASSED: END OF THE LINE
Fifty hours and twenty minutes later... Thank heavens. Decent ending. Very nerve wracking in the Revolver-Ocelot-tells-you-it's-been-a-long-time-since-you've-saved way. Had some pretty serious fps slowdown with the fire, however.
The bottom line is that you know it's a pretty good game when you keep working on it (apparently every Xmas break) for five years.
EDIT: Hey, look, who knew? Available on the Mac since Nov 12th of this year!