This game is awesome for all of the WRONG reasons.  First of all, Mario becomes PINK JAMMIES MARIO!  Pink Jammies Mario has the power of what I call the "Floaty Jump", which means he goes up, then floats up a little more after stopping.  He can also do a faux  "Double Jump": after jumping on an enemy, jump again to go even more ridiculously high.  For these reasons, I declare the game "So Bad It's Good", and a treat for just a little while.  Mario controls about as well as a really mad horse on ice skates in an oil slick and covered in grease and laminated, which makes this game FAR more challenging than the original Super Mario Bros.  I personally think it's a horribly done port: the first levels are identical to the original, except for, I believe, the first castle.  Enemies look basically the same, but when walking off a ledge, they go down diagonally THROUGH THE EDGE OF THE LEDGE and continue in that straight line.  After hitting another wall, they reverse trajectory, making for a... memorable scene in 1-2.  Mushrooms also do this, and, on the subject of power-ups, instead of having them appear in fixed places, there's a random(and low) chance that a mushroom or fire flower will pop out instead of you getting extra points.  There's no extra lives in this game THAT I KNOW OF, which adds to the "challenge".
In short, this game is amazingly bad.