Hello there. ROM hacks primarily came from modified versions of officially released games, from changes such as translation patches, to sprite/model swaps, to as far as entire rebuilds of the game, even reverse-engineered, like the "Sonic: The Ring Ride" series, the many Super Mario Bros hacks, such as "Time is Ticking" or "Super Extra Brothers"
Like TheTrueUlti said, if you entirely created the game yourself, it isn't considered a hack.
Game hacks to me, are honestly fun if you find one that makes massive edits to the original code. Sometimes, this leads to games feeling so different that it is a whole new game! Sonic: Color Contrast, for example, changes the game concept so you have to run around and explore in a grayscale version of known zones and find color monitors that restore the Mobius planet of its original colors. Sonic: EraZor, is another game that takes a massive turn on the original game concept, catered to experienced and skilled Sonic players, intended to be a bit frustrating. There are also Pokemon hacks that allow you to catch all the Pokemon without needing to use a Link Cable like in the original games, mainly because new gamers these days would be confused by what Link Cables were, because I remember them.
If you want to start ROM hacking, then you'd need to plan for yourself, what are you going to change about the ROM? Maybe backgrounds, character swaps, physics changes, or even tear the game into a new one? Really intensive ROM hacking requires learning a programming language, such as Assembler, which is what the Sega Genesis uses, for example. The "Sonic the Hedgehog" series is a great example of ROM hacks that do just about all of that, maybe all-in-one too!
Hello there. ROM hacks primarily came from modified versions of officially released games, from changes such as translation patches, to sprite/model swaps, to as far as entire rebuilds of the game, even reverse-engineered, like the "Sonic: The Ring Ride" series, the many Super Mario Bros hacks, such as "Time is Ticking" or "Super Extra Brothers"
Like TheTrueUlti said, if you entirely created the game yourself, it isn't considered a hack.
Game hacks to me, are honestly fun if you find one that makes massive edits to the original code. Sometimes, this leads to games feeling so different that it is a whole new game! Sonic: Color Contrast, for example, changes the game concept so you have to run around and explore in a grayscale version of known zones and find color monitors that restore the Mobius planet of its original colors. Sonic: EraZor, is another game that takes a massive turn on the original game concept, catered to experienced and skilled Sonic players, intended to be a bit frustrating. There are also Pokemon hacks that allow you to catch all the Pokemon without needing to use a Link Cable like in the original games, mainly because new gamers these days would be confused by what Link Cables were, because I remember them.
If you want to start ROM hacking, then you'd need to plan for yourself, what are you going to change about the ROM? Maybe backgrounds, character swaps, physics changes, or even tear the game into a new one? Really intensive ROM hacking requires learning a programming language, such as Assembler, which is what the Sega Genesis uses, for example. The "Sonic the Hedgehog" series is a great example of ROM hacks that do just about all of that, maybe all-in-one too!