Oh, I don't know... The huge wall thingy was kinda cool for me. I liked the challenge. Required skill and it was hard but nothing too impossible. Once you get the hang of it it's sweet.
I do agree that we could have some other kind of reward for it, like the "Will to Swim" or something, or a really cool-looking gate, a map, or an achievement. However, I felt pretty satisfied and didn't even felt the lack of anything till reading the comments.
That being said, the ending was a bummer.
 "This is not a minimalist game"){kind=icon}
 "The Valley Rule"){kind=icon}
 "FL!P"){kind=icon}
 "One Trick Mage"){kind=icon}