In the second sentence of the kickstarter page it says "a new rocket propulsion system powered by the Sun and propelled by water". I think that is pretty clear.
But suppose I had a Kickstarter for a car on the same premises: "A revolutionary car powered by sunlight and water - fill up with water every now and then, and it will run forever". No further details. Would you buy?
I think it's a very small percentage of the world that would know off the bat why "sun and water" could work for a spacecraft, but not for a car.
I think some more detail on the physics behind it, aimed slightly below say Physics 101 level, would help to convince more people to contribute.
It makes it simpler to distinguish this from "crystals can change your life" or "lose X pounds of weight in Y days" style marketing, which promise the moon but don't explain how their miracle is supposed to work.
They do give an explanation in their link[0], but I think having a summarized version on the Kickstarter page itself would help donations. (To be clear, this is a comment on the marketing, not on the physics or feasability.)
They could do a little comparison of existing technologies:
Chemical rockets - put fuel and oxidizer together, burn them, resulting gas is shoved out the back and pushes the rocket forward.
NERVA - reaction mass is heated by a nuclear heat source, resulting gas is shoved out the back and pushes the rocket forward.
Ion thruster: reaction mass (such as xenon) is charged electrically using a grid and the resulting ions are shoved out the back and pushes the rocket forward.
CAT: reaction mass (such as water) is charged electrically using a glass bottle thingy and the resulting plasma is shoved out the back and pushes the rocket forward.
Shove that in an infographic and you can get the basic concept across to someone who knows high-school physics and sound convincing to people that don't even have that level of background knowledge.
Upon reading the entire page, it looks legit. But when the page first loaded, I read "propelled by water" and immediately thought "Uh... aren't normal rockets also propelled by water?" I just think the kickstarter page could have been a little more upfront about the plasma part.
