I will tell you a bit of information about this ... it was a adventure developed for 5 years , that wanted to be the a Myst clone ... when it came it cost only 20$ , Dreamcatchers number 1 best sold game

... if you ask why it was only 20$, well ... its only 1h and 30min long ... since its a Prologue to the main game , it was planned to be published as a free game but the game development time was so long they pushed some of it as a vertical slice aka Prologue ... something like MGSV Ground Zero was
so your forced also to get the second game that came in 2004 ... since both of those make the whole game ... a adventure that was developed for over 9 years ...