Other than the great production in all aspects (acting, directing, make-up,..etc), the most important is the hidden question the author is asking; would it have been better to life our lives in reverse order, where we grow younger instead of growing older? If we were born old, then become younger every year, would life have been better? This is the real morale about the movie that was written 90 years ago!
My personal opinion is that it doesn't not the matter which direction is our life heading as much as we are making the best out of what we have. I guess the film supported that as well where it highlighted that the best part of our lives when wisdom meets action; i.e. in 30s & 40s, so let's make the best out of it.
What about you?