Ciao raga il bundle di resident evil mi costa 29 euro e no 25, perchè?

That's entirely beside the point. The complaint isn't about GOG's general bundle policy and pricing. And 2 out of 3 games aren't even available for individual purchase yet.

The real question is why the bundle costs 29 euros for the OP instead of the 24.99 euros that I see advertised here in Germany. The price should be the same within the euro zone, right?

 
  GOG uses IP addresses to determine the country and price region of customers. This process is not 100% reliable and detection can fail for multiple reasons: Do you use a VPN to change you IP address? Do you live close to the Swiss border? Do you use mobile Internet which may frequently switch base stations? In all those cases, GOG might detect a non-Italian service operator.

No, the One World, One Price policy is dead. Users in Poland have been complaining about a higher price than USD; even accounting for sales price.

Poland is not part of the Euro (currency) zone. Germany and Italy are.

so coz i live in Swiss i don't have right to 17% discount? Single game 9.50chf and bundle 28chf... very bad service! I fell so disappoiment :(

Switzerland is considered a rich country.
Cost of living there is also higher than in other countries.
If you can afford to live there, you should be able to afford the €4,- more.

The Resident Evil bundle is currently not discounted. You talk about the base price which is different in various regions around the world based on average income and economic power.

Switzerland is a rich country and can afford a higher price.
Many regions such as Asia and South America have lower income and their base price of games is also lower.
This exact same bundle costs only 11,61 Euros (converted) in China. Again, this is not a discount. If you live in Switzerland, you have to pay local prices. Simple as that.

source:
https://isthereanydeal.com/game/resident-evil-bundle/regions/