Do you like a good mystery? Then perhaps you ought to take on the role of Joe the janitor in the newly released The Silent Age. It's a point-and-click adventure where one lowly 70's janitor is tasked with finding out why everyone in the future is dead. Of course, Joe's future is our present. Yep, we're all dead.
Joe has a handy time travel device he was gifted by a dying man. After being launched 40 years into the future – to now – he starts putting together the pieces by hopping back and forth through the decades. You'll have to reason your way out of various predicaments to unravel the secrets of the future (present) and save humanity.
The Silent Age has a distinctly 70's vibe and really smart, minimalist design. It should run on just about anything, and it's free. The catch is this: it's only the first chapter of the story. To get any real answers, you're going to have to wait for the next episode, and I imagine they'll be charging for that one. The first taste is always free.