Undertale:Extended is basically Undertale with new areas and Boss monsters. it adds a bit of exploration to the game since most of the new areas and bosses can only be found off the main path of the game.
This will give a brief description of the location, how and when you can find it, and give the name of the bosses in these areas.
The "Freaky" farm- A freaky, haunted rendition of a human farm. It was built under mysterious circumstances and most monsters are terrified to go near it. The only things in this area is a empty feild filled with scarecrows in different poses, along a empty barn and a farmhouse full of Scarecrows. Their are two ways to find the freaky farm. You can either be told about it's boss (Stitches) by napstablook, or you can be given the map and dared to go their by Undyne.