The inspiration for this level naturally comes from the first world outdoor levels of the original NES Mario game. When making this level, I wanted to accomplish three goals.
1. Set a theme for the level
2. Make the difficulty very passable
3. Have Progressive Power-Ups
The theme for this level is flying coins, which you right off the bat when you start. Pay close attention to the first flying coin you see to get a hint. The objective with the flying coins was to make them part of the environment more so than something you should outright collect. In my mind, this is where flying coins live!
The difficulty was an interesting one because I didn't set out to get Super Mario Maker to make "Kaizo Mario World" levels. I wanted to make fun levels. So when it came to areas like the Piranha Plants, I set up unreachable areas to foreshadow their eventual appearance. The flying block obstacle was one area I went back and forth on because I wanted to know how many blocks would be needed to get safely passed, especially since I introduce the Lakitu at the start of the obstacle. I originally started out with just three blocks but decided more was needed for such an early level. To add a bit of distraction incase it was too easy, I placed static coins above the area.
The other area that I hope Nintendo eventually patches is the 'progressive power-ups' ability. Unlike EVERY MARIO GAME EVER MADE, Super Mario Maker does not allow Mario to get power-ups in a progress like way. For example, in all the original Mario games you have to obtain the Super Mushroom to become Super Mario in order to get the Fire-Flower. In Super Mario Maker, it doesn't matter what state Mario is in. If you place a Fire-Flower somewhere in the stage, Mario will get it whether he's regular Mario or Super Mario. To counter this, I added an obstacle early in the level where you have to get the Super Mushroom in order to progress and added two extra bonuses if you manage to stay in Super form for that long. Doing this was easy as all I needed to do was place destructible bricks underneath the "?" blocks. So if you're regular Mario, you won't get the bonuses but you can still beat the level at this stage.
Maybe when more tools and tricks are unlocked I'll revisit this stage sometime in the future. I'd love to add more flavor to it!