Yes but it only does this on one side of the iPhone, with the home button to the right. Star Walk will be upside down if you view it with the home button to the left of the screen. With other video content the program will flip itself.Not sure what you mean about landscape mode; this app always uses landscape orientation.
I would love to see this app show an above view of our solar system, not from earth. It would be interesting to watch the orbits of all the planets at different times.