Since multiple recent submissions have submitted incorrect times for their runs, there appears to be a need for clarification.

Full-campaign runs do not track in-game time.
Full-campaign runs track from hitting Start Mission on the first level, to the Campaign Complete text at the end, and all menu time in between. Then load times are removed (manually, as we don't have an autosplitter to use) to get the final time.

Time spent menuing between levels counts. You can and should prepare character loadouts in advance to reduce this time. The in-game timer is not used, as any slowdowns make it inaccurate.