A lot of times I've completely awakened consciously in my dreams. It's called Lucid dreaming. You can jump up in the air and start flying around like superman. The 1st time I jumped off a two story building was terrifying because it felt so real. One time while running I fell and hit my knee which hurt a lot. So dream world can be very real feeling. Regarding alternate realities, maybe by chance you might be interested in the Mandela effect. A lot of people are posting youtube videos on it. A lot of Mandela events seemed true to me, but the biggest one that made me feel it was real was the Star Trek one where Picard often plays with this big long crystal in his office. I was like "WTF, I've NEVER seen Picard fiddling with a big crystal in his hand before on any episode." After some research it turns out to be true.