Add to this that the fixes made for the blaster only work on some systems but not others, the tutorials don't seem feasible at all as part of 100%.
Tutorials don't count towards the actual game completion score, so I don't think they should be required. That and they would be rather annoying to run through as well. Not to mention that the final tutorial may end runs due to the requirement of using Sonic Blasters, which are notorious for crashing the game. So my take is that tutorials should not be counted as part of 100%.
I strongly disagree that the debriefing should be counted. I think the level time should end when the menu disappears and things start to teleport out. End teleport should not be recorded either, except for maybe full game runs.
I'm quite curious to know what the rules would be for individual maps, mainly because there is a grey area in where to stop the clock in certain cases.
Personally I think the timer should start as soon as the mission briefing appears and end when the last crystal is counted on a map.
This doesn't clear up maps like The Path To Power, however. Completing the Power Station has a delay of a few seconds (due to the message being played) before the game counts the mission as finished.
Another case in point would be locating trapped Raiders or guiding them home (Breathless, Search 'n Rescue, Run the Gauntlet).