It is likely that the develop would be found liable by a court for:
Breach of contract
Breach of fiduciary duty
Breach of good faith
Two important quotes about this matter (both
featured in this video):
"As a company you shouldn't take people's money by making certain alluring promises, spend that money, and then when things are going well for you back-track on promises before giving the money back when customers' money and satisfaction is no longer as pivotal for your long-term success and survival. Customers aren't there to act as temporary interest-free loan services, they are there to back projects so they can support the fulfillment of certain promises. And as far as games go, ensuring they release on stipulated platforms is an important part of that. Add on as many platforms as you want, but do not take away any of them, especially if it means breaking your word after you have people's money and done what you need with it. It will only make backers feel like they have been used and exploited, rather than valued as huge contributors to getting the crowd-funded game off the ground."
"I think what makes this particularly galling is how they basically used us backers as an interest-free loan. They took our money, developed to the point where it was mature enough to attract external investors, then totally changed the game plan and fully expect us to withdraw our cash, since they're now out of the high-risk phase of the project
The conned us into lending them the money, and manoeuvered it so we'd be sitting on the bill if the development project failed. For a game that sold itself based on community involvement, with backer builds and all, this is just awful."