Note: This deviation is the original 2005 version of this picture. An improved version from 2011 can be found below:
As you guessed, an hommage fan art to the famous video game all-stars!
The Mario Bros. are in some sort my cult characters, since they got my hands stuck on my S-NES controller from my tender youth until I got 12, when I turn my back to them. It's not until recently I got into it again (in some non-abusive way though), when I bought my GameCube console.
This is an hand-drawn picture, realized on smooth Bristol carton-like paper, then brought into Photoshop. I'm glad the basic drawing didn't have to be improved in Photoshop this time.