In video games, I thought Final Fantasy IX held up really well, but Final Fantasy VIII was much less fun than I remembered with a much more nonsensical story.
And also a video game, the Story of Seasons game, A Wonderful Life, was not as much fun as kid me remembered it being. Farming games have so much content these days, these thin games from the past don't really compare.
I reread The Hunger Games trilogy last year, and book one held up really well still, but book three was much less tolerable than I remembered. (Gale was so mean to Katniss! The whole book! Why did she like this boy?)