I have a question about what does it change in the base game / base recipes? Is it vanilla factorio with "just" added recipes/mechanics in the end game that you can completely ignore until you reach that or does it change base recipes and alters the vanilla factorio experience already in the early game?

Hi,

It's almost "just added recipes/mechanics in the end game" and can be added to an existing save :)
There is only three earlyer things:

• Highly calorific fuel is unlocked with Biter egg handling. This new fuel is made from eggs and jelly. It can also be used in heating tower, tank and locomotive. The fuel's acceleration bonus is 300% and the top speed bonus is 110%, making it a slighty more attractive option than nuclear fuel for short distances.

• The Heat increaser is unlocked on Aquilo. It allows a steam temperature of 800°C to be reached, and Steam turbine now works up to 800°C, with power gain.

• The Cargo bay unloading max distance is nerfed at first (but there is techs to increase it when you have the pack).