Summary
Shadowrun Returns is a turn-based RPG set in the Shadowrun universe in 2054, where high fantasy meets science fiction.
Shadowrun Returns Review for Mac OS X

Shadowrun Returns is actually two games, tied together with a strong and unique setting. The first game is a single-player campaign entitled "The Dead Man's Switch". The second is an engine for making your own campaigns, and/or playing through those others have made. Potentially, this second game could prove to reason to buy Shadowrun Returns in the long run (and I think it's safe to say that the developers are banking on this, given it was a key feature in the original Kickstarter pitch, as opposed to a stretch goal as is the usual fashion). At the time of writing however, I can only comment on the included campaign, as there aren't any significant user-created campaigns available. That said, I think it's safe to assume that many of the strengths and limitations of The Dead Man's Switch will be factors in future campaigns too, and if the campaign itself isn't compelling enough, it seems unlikely that people will want to make or try out other campaigns.