This is some basic stuff and mostly obvious at this point but since there has been some confusion I wanted to make this post to clear things up and give it some posterity.
[section=Full-game runs] Timing starts on character select or on "Are you sure" if New Game+ is not unlocked.
Timing ends after you hit a button to remove Mike's last dialogue box. ("Your replacement is out for"- etc.) The dialogue box itself doesn't have to disappear just the text.
[section=Individual Levels] Timing starts when you hit the floor. At the very least it should start before/as you make any inputs coming out of the pizza box. New York ILs start the same as full game runs.
Timing ends when you grab the level end pizza or yoyo.
While I'm not sure how much help this will be here are my notes based off Xerian's 1:30:07 run and additional knowledge from the forum with some safety meds routed in for new runners. My current PB is a 1:35:37 with this route. http://pastebin.com/92XFCsyC I'm fairly confident in these notes except for
- Triggering the second phone call by dropping back into the hole is not confirmed to save time yet.
- The Final Jack fight as it is complete and total chaos.
You certainly can get the eye under his tail without having him climb up again but I have yet to figure out a way that works for me.
I'll write up a longer explanation for the route and how the triggers are known to work soon. Critiques are welcome.
Here's a longer guide explaining some of the triggers and a couple mechanics. This only takes you up to the the final Jack fight for now and I might expand on it later. http://pastebin.com/AfLvdBnp
EDIT: Added an order to the final jack fight based off this post by Rebecca13 https://www.speedrun.com/re7/thread/mp68g Turns out you just have to crouch. :|
EDIT2: Added longer explanations for the sh¤t speedrunners do.