I've never seen it do that. I'm not sure how much I can do to optimize, renpy isn't really an engine you can optimize that I'm aware of... But I'll certainly look at the documentation and see if I missed something.
What platform are you playing on?
I just tried skipping through all of r2.0 and this was average stats:
View attachment 1200066
The biggest peek was: 10% CPU, 650~MB, and 19% GPU.
Idle with no animation: 0.3% CPU, 487MB, and 0% GPU.
Idle with animation: 1.5-3.5% CPU, 640~MB, and 15-22 %GPU.
(For animations I just averaged between some minimal and max movements, it's just video.)
You said you're running on a local version of the engine, maybe that is causing issues somehow?
As to content, yes. I do plan to add more expanded sequences here is the post talking about the plans for r3.0:
https://f95zone.to/threads/rick-and-morty-another-way-home-r2-0-night-mirror.79138/post-5721805
Edit:
It's also worth mentioning that the Python in this project (outside of the engine which I am using stock as provided when building) is VERY limited. Most of it is in scripts.rpy (to make data structure classes and some variable setting functions), and messaging.rpy which runs the "text" messaging parts of the game. All the rest is just basic renpy dialogue and images.
I also spent a good portion of today looking through both renpy documentation and help tickets and there is no mention of this issue. So, uh... I don't know what more I can do to optimize for you if I can't reproduce the problem.