Dark Souls II is the worst in the series. At this point it's only worth playing if you've played everything else in the series and aren't tired of the formula.

It's on humble store, they only sell PC games.

That PC Gamer list is really poor, but even so Dark Souls is a much loved title. #2 of all time is pushing it, but it would likely make my personal Top 10. It has incredible world design, it's storytelling methods are really cool (you can piece the story together yourself or you can ignore the story entirely, it's never shoved down your throat) and progressing actually feels really rewarding as it can be a very hard game. If you like RPGs at all then it's a must-play title that's for sure.