Less than a day until the sale ends... which of these games to buy? [UPDATE: Made the decision]

In regard of your play time in your library. I recommand you Dex.
Have a good day ;)

If you could get a couple of titles, then, Rage, Prototype and Metro
Metro is pretty much my favourite game, completed both parts non steam, from what i've heard redux doesnt change the story, its mainly settings and some fixes, the game is very atmospheric, scary(for me) and hard.
Rage is like a darker borderlands with less weapons, but its fun and for the current price a really nice game.
Prototype, well I can't say much about it, but it's fun, though I didn't really like the story that much :)

Update: I finally bought Metro Redux Bundle and Pony Island. Thanks for all the helpful comments!