They don't say much about how well these suits can work. Are the just for protection or do they actually enable human functionality in space? Zipper on the bac

They don't say much about how well these suits can work. Are the just for protection or do they actually enable human functionality in space? Zipper on the back? I sure hope they have a rope you can use to pull it up your back. This sounds like one of those design details that movies use as plot points. For example, on a space station a disaster depressurizes a central capsule. A single astronaut is trapped with a suit on one end of the stations and because of a zipper at the back of the suit cannot be rescued.