I've been guiding my buddy through AO, and he finds the puzzles absolutely maddening (bats especially). Of course, I'm telling him where all the secrets are on his first run, so it's unfathomably harder than it normally would be.
We spent a good hour getting that secret in the Paramonian temple right. The one where you have to lead the Mudokons to the portal while the Paramites are eating. That part wasn't so hard, but he could never get past the rocks that start to fall after the portal closes.