This is more-or-less what I envisioned the world of Super Mario Bros. as being like (well, except for the Koopa Paratroopas being sea-turtles) back when I first played the first game. I was a little bit disappointed by the cartoony style of SMB 2 & 3, and even more disappointed as the series just got more and more cartoony over the years. It's nice to see some art of the exotic and dangerous alien world of the Mushroom Kingdom I fell in love with as a kid.
Actually, they were brothers, just one was adopted (which I thought was a great add to the development of the story, no matter how much the move sucked) and really, in all truth the Goombas are taller than Mario and Luigi even in the games, remember? It isn't until you get a mushroom and grow bigger that you are actually taller than them. Otherwise, they are just a few pixels taller. Just saying, don't mean any offense. I didn't like the movie much either.