The MGM movie and the Grimm story of Hansel and Gretel are actually very similar. They are about two poor kids, a boy and a girl, who are forced to go into the woods where they find a gingerbread house with an old woman who offers them lots of sweets. The old woman wanted to eat the children but eventually died in her own oven. There are some minor details that are also the same. In both, the parents are blood related and the moms are not step moms. Also, Hansel used a chicken bone to make the old women think that he was still skinny. At the end, the children had to cross a river to get back home, but they crossed it on foot instead of riding a duck. Though there are a lot of similarities, there are actually several things that are different in the story and movie as well.
In the Grimm story, the mom was portrayed as this evil woman who just wanted to be rid of her children for selfish reasons, just so she would be able to feed herself. In the MGM movie, the mom was a very unpleasant person, but she only sent them out to the forest because she was frustrated with them, having no intentions of them possibly dying out there. When Hansel and Gretel were getting lost in the forest, the story had them find their way back using pebbles, but the movie had no mention of them using pebbles at all. In fact, the movie made it so that they were not even able to make it back home until they found their father at the end. Some of the occurrences were different in the movie from the book as well. In the movie, out in front of the gingerbread house were several giant gingerbread men. We later found out that those gingerbread men were actually other children that had gotten lost in the forest and cooked by the old women. Also after Gretel had gotten the old women in the oven, the house basically exploded and red foam started pouring out of it. Nothing of these sorts happened in the short story at all.
The movie directors of the MGM version made these changes probably because they wanted to make the plot a little more dramatic. They most likely thought that their audience would much rather see a house exploding then just two children running away. Also, they probably didn’t want to make the mother seem as evil as she was in the story, so that’s why they didn’t have her take them to the forest and leave them there twice, and that’s why they never needed pebbles. I’m sure the movie directors also wanted to put their own twist on the story when they made it so that there were lots of children getting lost in the forest and no one knew the reason why. The changes they made were logical and still made their story flow well, though it wasn’t completely true to the Grimm story.