Gurumin is simply a great game.
The lead character is a child named Parin who is the only child in mining town. She meets friendly monsters who can only be seen by children. When she learns that these monsters are in trouble she quickly decides to help them. The story is typical RPG fare, but the dialogue makes it entertaining. She is given a drill that can be upgraded to fight phantoms. Its easy at first, but there is a considerable challenge as you continue playing.
The camera can be cumbersome on certain levels, which is a common annoyance for a game of this design. However, it is not something that will make you want to give up playing. My only other complaint is that Parin takes damage she is not wearing the proper gear while in water. Why is water such a deadly presence in video games? Anyway, just buy it. Its only 16 dollars and is worth more.