RTpro This game has a wonderful atmosphere!
It was quite challenging because the Spine files were very heavy for performance so I was needed to limit the numbers of bones and meshes.
Spine skeletons are generally lightweight, but it is true that performance can become an issue when a large number of skeletons are displayed on screen at once, as in this game.
I am not sure which version you were using when you created the animations, but runtime performance has also been improved in newer versions. If you work on animations for a similar game again in the future, you should have a little more flexibility by then.
In any case, thank you for sharing this!