There are many ways to tell a Shakespeare story, and there have been many different versions of Shakespeare's plays because there all really good; and I suppose if you create characters and stories that are so memorable there is a desire to see more of it, in many different ways. There is only so much you can do, only so many times you can imitate a shakespeare play and again, and again, and again.
In this version, the neighboring gardens of Montague and Capulet are at war, but the gnomes, Gnomeo and Juliet, are in love.
I think there is something about the comedic side of this which make it all the more appealing, to me anyway. Overall