If we customize a software product in our company, then the customer has to pay for the work time. Even if it does not change the basic software. Somehow, we have to monetize our working time. If the customer doesn't pay in the end, he doesn't get the software customization. Now L&P has the problem that he can not protect his software (game), or the protection would be bypassed very quickly. That means for the developer he can't compensate this feature/work time, which obviously cost him more effort than he expected, probably by more money. Because he has to expect that the game will be available to everyone again shortly after the release here. That's why I can understand the attempt to financially compensate some of the additional effort via this prerelease, i.e. to get paid additionally.
But, and now I turn around my earlier posts here and apply them to L&P, just as his supporters give him money voluntarily and bear the risk if he doesn't deliver, it's his risk if he misjudges his workload. And it is unethical to then charge more money.
So if one of his 30 Euro supporters would come here to this forum and complain about the rip-off and would talk about milking, then I would be ready to give this person, in this case, unreservedly right!