I believe that good game design may not necessarily have exact guidelines, but rather it just has to work and be fun. Since I've been playing games my whole life I personally feel as if I have a somewhat of a video game "intuition" so to speak.
If someone makes a game and I play test it and feel that something isn't just quite right I make a suggestion to change it. If I make something myself and play it and just don't think its fun I try and change it as well.
I believe that if I'm not having fun playing something then other people aren't as well. Here is one example of something I suggested to my good friend who is working on a Link to the Past hack.
Here was the original overworld screen by Seph
and here is my modified version.
Would you agree with my design changes?
I deleted a barrier in the middle because I felt that it was too cramped and fixed a perspective error on the far right high level hill.
Here is a link of a preview of the game. Its by the same person as Parallel Worlds hack.
https://www.youtube.com/watch?v=ONgjEp4YOg4