Thanks for posting the English rules, my Italian is sadly non-existant. I read through the rules but haven't had the chance to play, so bear that in mind.
I think the game has a really strong theme and voice, i really like the idea of interacting with the cardinal themes and I think the questions you have as prompts are very evocative. I also like the mechanism for interacting with the island inhabitants and the way the different factions seem to play off each other and require the PCs to get involved. It's something I'm curious to see how it works in actual play. The concept of going to place to place to interact with themes and philosophical questions and people and societies that are defined through these themes brings to mind stuff like the original Star Trek - and I mean that as a compliment. :-)
I did, at first, find some parts of the rules to be a little bit hard to get. That might have to do with the translation, but it might be that you'd benefit from writing a short description of what the structure of play looks like. Maybe something about the way a single session focuses on one island while the campaign can encompass the whole archipelago, saying something about PC actions and interactions and introducing some key concepts? There were some concepts (like value and reputation) that were introduced in questions before you explained what they were and so on, and that can make it a bit hard to follow. But I think this could all be solved by looking over the text from beginning to end with "fresh" eyes and thinking about how you could structure it or explain some things up front to make it as intuitive as possible to learn the rules. An example of play would also, I think, be super helpful if you want to further develop this game.
One thing I didn't completely get was the way the different time disturbances affect the actual gameplay. But that might very well just be me reading that section a bit too lazily. Still, maybe worth thinking about if that is a key part of the game that you want to really emphasize then maybe it should be even more tightly integrated in play. Or otherwise, maybe think about whether it's something that you could do without and get a more tightly defined game?
Anyway, good work, I really enjoyed reading this and would consider playing this with friends so thanks for sharing!