Haha I had to do lots of reading on it afterwards. Then I went again and I still found it hard to follow. It makes sense in my head but there’s still some parts I don’t get.
They are able to go in reverse but they technically can’t affect anything because it’s already happened so I don’t actually know how they can’t actually alter anything?
There was lots of inverting and reverting back by Neil during that final battle, it was difficult for me to follow live. But in reading about it further afterwards, he was doing this purposely in order for him to influence what was happening after the cave entrance was bombed in, with the Protagonist stuck inside.