A number of factors make it easy for me to state that I still think this is the most important science fiction film ever made, despite some of the acting, outdated dialogue etc.<br /><br />First, there is the scale of imagination in describing the Krell, a humanoid race native to the planet, now all dead, who were 1 million years more advanced than Earth humans(us), and their technology, particularly the 8,000 cubic mile machine.<br /><br />Second, there is the music and sound effects, which are inseparable from each other. It creates an eerie, unearthly feeling, unlike "2001", which had traditional classical music.<br /><br />Third, its "monster" is not only the most powerful and deadly ever envisioned, it's also based on real science and doesn't break the laws of physics and biology.<br /><br />Finally, and most importantly, Forbidden Planet is the only movie ever made that attempts and, more incredibly, succeeds in making an honest, intelligent and mercilessly logical statement on the limits or ceiling of human (or any other biological entity's) development, no matter how long we survive as a species.<br /><br />In other words, it predicts our inevitable destiny.