I think that nobody has noticed the closed door way above the open one. It seems too high to reach, but it is attainable. I just cannot play the game right now, as the game does not aggre with Vista. Strange.
On level 20, you have to grapple to the moving block. Then you extend the grapple rope and swing clear of the lava block when you are clear, you reel in the grapple rope untill you swing clear of the lava block.
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