And although some of them are only relevant when the player is in a space dimension, some of them are used on the Overworld too. All of these things are fundamental to Galacticraft - we can't really switch them off. And in GC3, the player character will be tilted if you tilt the rocket you are flying in (and maybe in future in a few other situations too). There's other stuff too, to do with using rockets.

Galacticraft also makes other internal changes to how players work, so that for example the player will take damage if in an airless environment, and the player will not take fall damage if falling with a parachute. The reason is that Galacticraft changes how the player looks in 2 ways: it adds the helmet and oxygen tanks if you are wearing those, and it slows down the limb animation when you are in space, so that for example if you go bounding across the moon your arms and legs will not be swinging around like crazy. (My guess is they would also have problems with each other, and with MorePlayerModels - if somebody knows otherwise, please say.) Galacticraft has visual compatibility issues with any other mod which changes how the actual player looks - so other mods like Animated Player mod and Smart Moving will also have problems with Galacticraft.

More player models 2 mod