So are these games or e-books? I'm a bit confused by the various descriptions.
They're choose your own adventure books that run like an interactive story. I had The Forest of Doom from a previous bundle (humble weekly: RPG Book 1) and gave it a try last night on PC. If they all work like that one:
It acts like a CYOA book, turning pages and being asked to go to different sections depending on choices. Some items result in battles or skill checks, with dice rolls to determine win/fail, attack, etc. (depending on stats you rolled at the beginning of the game). I played through the Forest of Doom in about an hour and a half yesterday, somehow managing to pick the right items/directions and not dying in order to finish the story.
I'm debating on this bundle myself: $9 for 10+more games of a design that interested me, but it's not exactly a bundle I jumped on the minute I saw it.