Amazon.com Digital PC Games

Has anyone here purchased a digital copy of a PC game from Amazon.com? How does it work, do you have to run the game through a program similar to Steam or is it more like a GOG.com game? 

Several of the ones I bought just gave me steam keys. Not sure what their other ways of distrobution are.

Well I am interested in Cursed Mountain for the PC and Amazon.com has it for $4.99 but it's a digital copy. Cursed Mountain is not on Steam so I am curious as to how this will work.

Anyone?

I know someone will come along with more info, I hope

Most of the games that I've gotten from there are Steam keys. From time to time I do get a game that is a standalone version. Not sure if this helps. They do have good prices from time to time though.

Well I guess I will just purchase the game I am interested in. It's only $4.99 so why not right?