My friend (Achilles) found a way of entering the opening demo scenes using the reset feature on the SRT. All you have to do is wait for the screen to go black with the text on, press F9 to reset and wait. for some reason this causes you to gain control of Jill after the text screens have finished.

The first 2 demo scene's are pretty useless as they are both fairly early into the run and there will be a strange bug that causes any healing to put you in the danger condition.

The 3rd demo scene however has you start outside of the train with the dogs allowing you to grab the wrench at the start of the game and not have to backtrack later on. After a bit of testing i found that it is possible to complete the game from this state and the healing bug present in the first 2 scenes is not present here.

As of yet i have not found a way to replicate this without SRT and although SRT is currently allowed in runs, i have a feeling this is a step to far (lol) I believe sub 40 may be possible but i am not skilled enough to test it properly myself

Ive been sitting on this for a while now as there was a debate about SRT that had recently happened and i didnt want to restart that so soon.

It seems that opening your inventory on the frame the barrier is supposed to drop allows you to play the barrier dropping scene and rope burning scene at the same time

i have not yet been able to reproduce this so it could have just been a glitch and it would only save maybe a second or 2 on runs with the medium barrier drop. Sorry if this is already known i did a quick search before i posted but couldn't find anything.