The one glitch I found in Mario World was on level two when you go down the tube to collect coins I jumped on the vertical tube and ran on top jumping trying to hit the higher blocks to break. Did this three four times and jumped just as I came to the wall and got hung up inside the wall and had to restart the game. Level two may be wrong as I haven't played Mario in a lot of years.
Weird - Wacky: our daughter could play Mario world start to finish with her back to the TV and beat the game with pretty impressive scores. She did this by the music and t could tell her where she was in the game. An amazing gift, and way too much time on Nintendo.