You can check out the project here: http://www.kickstarter.com/projects/448333182/call-of-cthulhu-7th-edition?ref=live
The stretch goals are a little hard to understand on this one but they seem to be all aimed ad adding to the end products. They are adding things like art and hand outs for the players with bonuses. The one thing that is weird is the bonuses seem to be applied to products which the kick starter is set up to create. If you are just getting the investigators book it does not seem like you get all the stuff that is added with the Keeper book or screen. They really need a chart to keep this straight for us. I guess the best advice is to get as many of the books you are going to need to run the game at once. So get in with the Malevolent Mi-go level at $70 seems to be the sweet spot. Or go digital and save cash.