The game is slow because KST coded the scene changes to load all the assets that is available for that location every single time, and then just hide the assets that are not supposed to be there causing a scene change to eat up CPU and HDD resources.I've always wondered why this game is so badly optimized. It's the only game I've played that runs very badly for a 2016 game
I understand the coding part, and Unity has its problems with the gpu if it's not handled properly. If I understood it better, I'd even try something
I hope that one day this game becomes a little more accessible, even if the dev is working on another project.
This is the main reason for the long loading times so it can not be optimised without a full rewrite of the game code.
There's a cheat mod done by xorxorrax that speeds up the scene changing times if you are using a fairly newish processor (6th gen Intel processor and above) I play the game on a 4th gen i7 processor and it speeds it up a little, but since the processor is lacking newer instruction set found in later generations of the Intel processors range it's still slow.
Cheat mod 2 is currently the best one to use though it could use some updating to add later content unlocking, but it still works fine.