Looking at sonic retro, there is tons of rom hacks there, not one to my knowledge is being targeted, but then the same thing happened to Bombergames Streets of Rage Remage game, Chrono trigger Crimson echos, and even the chorno trigger resurrection, while some rom hacks change from minor things like gameplay, sprite change to color pallet or character, or full scale game based on original concept into a new one, or just a translation, i don't understand why SOME games are ignored and some are not.
Pokemon, yes, is a very big deal to nintendo as it the game "You all keep buying for the past 20 years" But it makes sense i would thing, unlike the dozens of sonic genesis, super mario, nes and snes, and the SOR Remake, chrono trigger and some translation projects, which has not gotten any attention to their series for over 2 decades, get sudden problems with fan projects and property holders with stuff like this.
All i can understand is that nintendo and gamefreak reserve rights to the title and assets and anyone using them without permission is not allowed and has been target while the same stands for sonic and SOR games by sega and they are not any different from what i know.
There are many types of intellectual property and quirks with all of them.
The big two for games are copyright and trademarks, some do patents but that gets tricky as the US and Japan recognise that software can be patented where most of the rest of the world finds it a disgusting concept and opposes it heavily whenever a company/law maker floats the idea.
Copyright protects the work as a whole and individual elements thereof (the graphics, the music, the script, the videos, the level layouts....) from being copied without permissions. As many hacks will be using their own original works (or at least those of some other copyright holder) and get distributed as patches then it gets tricky to do anything about it. There are ways, most notably derived works, but that gets very tricky, very quickly and would ultimately have to prove damages. Also yes that would mean translations of the original Japanese script would fall under this, for a related series of actions see when subtitle sites came under fire for just that reason.
It is also when the makers of medabots, robopon, demi kids, yokai watch and all the others can make a game that is clearly inspired by pokemon but as they don't use the levels, music and whatever else it is all good.
Trademarks are a different matter. You register them every ten years but you can do so indefinitely. The prevent others from using the name, logo likeness and more. The idea being to prevent confusion among the general public as to what is a legitimate item from the original creators and what is something else. A key part of almost every place that has a trademark setup is genericide. This being when you allow people to use the trademark name without slapping them down or getting them to buy a license or something then a judge may well declare that you have failed to maintain control of it and the trademark is no longer valid. They don't have to go hunting round every small hack site there is for such things (
https://www.eff.org/deeplinks/2013/...-require-companies-tirelessly-censor-internet ) but when you stream it on popular channels and get traction on some of the main news sites for the consumers of the work it gets tricky. That it was pre release is even better as lawyers dislike pissing into the wind as much as anybody.
If you allow fan games to flourish you risk having it said that you no longer uphold the trademark and can lose it. This is bad for as much as Sega have let Streets of Rage languish in recent years it is still a mega popular franchise and work in their stable and their entire business is having things in their stable.
The extent and, barring the script stuff I mentioned, type of the change matters little when compared to "selling" your work and making it appear somewhat like a legit game in the franchise -- the pages used words like official and had all artwork and the like, fun as you like to make and play with but does cause lawyers to get excited. If it had been released as just another level hack we would probably be having this conversation for something else, though it would probably not have been as popular and though popularity is not something I seek I can see others wanting it.
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