Mostly the viewers tend to watch shorter videos. But it depends really on the content. If there is a tutorial (like here) viewers would whatch until the end, no matter if you make more videos with less playtime or lesser videos with longer playtime. Because they want to learn something. And if its good, they keep watching.
But overall you should make it depending on the content itself.
Makeing a video about "a scene" and talk about all possible stuff you can do there would stretch the video too much because there are to much sub points you can talk about here and most points are maybe not good to talk about in the beginning because they build up on a separate topic you may talk about later either way.
For my tutorials i planned to create a "demo project" and explain while doing all the neccessary stuff. So intracting with the objects in a scene will come after i introduced to interfaces as a separate video. Interacting with items on an object or on a character will first come when i talked about the item/inventory system ...
This will lead to several more or less short videos (10-15 (or 20) min) but sometimes i take my time and give it a 30+ minutes to do e.g. a coin/scumm interface because there is more to explain. I guess the playtime will raise after some time because the topics get more complex...
As an advise for you: Keep it like you did in the first series. These were great for beginners and gave a good overview.
Would love to see that Icecream shop again