Depending on the "how" they develop the game, the size should probably increase slightly, especially the code. They could've reuse the character's pose or make new ones, even the new art of locations and places.
In Ark: Survival Evolved, their size is so huge that the average computer, even the new ones cannot install due to the huge download size. So, I could guess, it game size could increase for every chapter, unless they refine it.