I've recently got into YI hacking about a week back, and I have now finished my first custom YI level.
It started out as a test level so I could get more familiar with some of the sprites, options, and such!
However I was able to turn it into a full level. I will add a link to the video footage of it! Enjoy ! Though keep in mind I am still a novice.. so any mistakes you see are because of that!
Also, the level wasn't made with red coins and flowers in mind, well sorta but not fully. Most were added after the level was pretty much done. So the level is more about gameplay then collecting coins and flowers! Also Yoshis were hurt in the making of this video. Sorry Yoshi!