Hi, I appreciate your feedback, and since I made the engine I can give you some response to your remarks
1. Regarding the last choice, it does make a micro save every time there is a choice and practically you should be able to press it as many times as you want to go backwards until the start, ,and if it doesnt work like this then there is a bug. The whole point of this was to avoid making people having to make 5000 saves, same with the replay system. But hey, it's an old habit that come from playing renpy games where you save around every corner because you know that renpy is extremly unforgiving on that matter. VNgine is designed to be able to also jump back and test a different choice if you wish, but obviosuly some choices affect something way later down in the story.
Regarding skip feature. First of all, Ren'py doesnt even skip forwards most of the case, it only lets you skip things you have played. Please correct me if I am wrong, its intended not to skip sertain things in the game by design and wait for you to take a choice. If there is a problem with the skip its the first time I have heard about it now for a long time and feel free to make a report. What you are taking about "not stopping skipping" it sounds to me like you clicked the "dialogue history" button in the corner not skip. Skip can also be done by holding down shift FYI.
Regarding tearing in videos, this is heavily dependent on your hardware, it is a fact that some animations flow better than others, and it may just be the case with how the animation was designed, its not always perfect, its an area also where motkeyz is improving more and more through the updates. We've been able to play the game on total potato pc's and most of the time it works pretty well, but indeed it can be noticed on some animations more than others. It has nothing to do with the engine, its just a codec running on your PC as all the video is webm vp8.
So please if you actually find problems with the engine you can DM me and i will take a look at it if its something that needs to maybe be tweaked or if its an actual bug, because not everyone reports bugs unless its totally game breaking.
Thanks again for the feedback. hope that this clarifies some things.
/A