The project is currently designed with flagship devices in mind.
The animation-heavy parts use a significant amount of memory, so a device’s RAM capacity is quite important.
At this point, my understanding of optimization methods has improved a lot, and it seems possible to optimize those scenes further. However, doing so would require rebuilding them almost from scratch to achieve the same visual results, so their modification priority is currently low.
As for the side stories, the gallery content unlocked through them includes one illustration for Gahel and one for Elred, one each.