Keep a close eye on the Elum's feet. He has long feet, but you only need to keep an eye on the tips of his toes, as these are the only bits that will touch the ground before he jumps. Only when they're at the very edge of the platform should you jump. And if it doesn't work - try again! You've got infinite lives, and that's the only way on through the game.
Incidently, you don't actually need to kill any of those three Sligs, as you can just run past them on the Elum.
