Ah yes. Kerbal Space Program :-) What a game .. Actually I would not say it is a game for everyone. It is in a funny world and looks pretty neat - with all that clumsy little Kerbals in it.
But in the end it is a serious Physik and Space-Physik Simulation. It is NOT for Action Fans. It is for technicans, for people liking to build working stuff.
So you have to built your rocket from distinct parts from example, different stages for the start to get it in orbit, get it to moon and such things And in the end bringing back your kerbal pilots on your home planet.
This game is very engrossing and very enjoyable. But it is not easy. It needs to get learned. Learn about Physik and such things.
But if someone would ask me if this game is worth the money: Definitely worth it!