This would a perfect film for an update. It's an obscure Japanese science fiction tale that did NOT have giant monsters. What it did have was starfish aliens. They are pretty bad costume wise, you can clearly see where the costumes were stitched together. They were so bad, I swear the redesigned the costumes mid film, or at least lit them better. Anyway the starfish aliens want to contact humans cause they have something important to say. For some reason though the Japanese are deathly afraid of starfish so they always run away ala people seeing Casper the friendly ghost. So the aliens change themselves into humans with cool slinky special effects. Now everything is ok and the aliens can finally give their warning. Earth is doomed because another planet is going to run into them, oh and stop meddling with super explosives. All the nations put their nukes together and shoot it at the offending planet. Meanwhile things get hotter and natural disasters are everywhere. The nukes do bupkis and everyone gets ready to die. Wait! There's an earthman with a theory for a superbomb. The aliens use their tech and his theory and they blow that planet to nothing. Turtles come out to play and children sing. Hooray!! Aliens say good bye and slinky themselves back to starfishes. The end.
Well of course the first thing to do is to make the star fish aliens look better. That shouldn't be too hard. The second thing I'd do is get rid of the runaway planet. It's a stretch to say the least. Besides we already had Bruce Willis blow one up. Instead, let's turn to global warming. Say some scientist invented some process that goes completely Apecrapilipitic and the earth goes through super fast warming. Now, the "\warning" of the film is strengthened. On the one hand humans nearly kill themselves, but at the end it will be a human that will have the solution. Anyway, that's the road I'd go. Nice disaster footage with the added bonus of aliens. Can't lose for trying is what I say.