There's no visible way to get past the blue man in the south, but there is an INvisible way (and yes I know it's a bit of a stretch haha). Here's a clip demonstrating how to do it (around the 10 minute mark):
I did, in the end, resort to that video walkthrough. That's the one puzzle in there I might call unfair; everything else was occasionally very hard, but tractable. (OK, I might have sworn a little bit during the block puzzle on the final continent, when I'd finally gotten to the point that I could move the blocks, only to die in a sand trap. But not unfair.) Well worth playing.