This video shows how to unlock the Balan costume in Balan Wonderworld, along with the "Tim Legend" trophy. This costume allows you to practically fly over levels, making it the best costume in the game.
This is without a doubt one of the most unreasonable unlock requirements I've seen in any video game. I have no clue how someone even figured this out, and I do not take credit for the discovery.
The method of feeding Tims itself is quite tedious. If your desired Tim grows big before having all 3 badges it won't follow you anymore. Additionally it's possible to have your small Tim grow big while it's feeding on the last set of gems, leaving you with 2 big-3-badged Tims.
Oh, and I hope you didn't waste all your gems yet. There appear to be a finite amount in the game.
Besides that, the small Tim badges are barely visible, and there's only a very small percentage of chance for King Tim to even spawn. (As I mentioned it in the video, it took me half a day of closing and re-opening the game)
Having tricky puzzles in video games is not an issue by any means, but when your puzzle basically REQUIRES a guide to solve you may want to re-think your game design.