The title is pretty generic, but this is still a nice picture. I mostly appreciate it for using a unique style but still being loyal to the Mario games. Yep, this is based on the most well known Mario level. In fact, that's probably the most played level in any video game! Is that a green bush? It certainly looks different than the clouds.
Everything is finely detailed here. Maybe it's a bit too big. You still use negative space pretty well. Mario looks like he's scheming. It's something about his hands.