Seeing the same cast of characters follow one continuous plot over 20 years of publication is common for comics and books, but it almost never happens in video games. Games series tend to either have a new cast and plot each game, like Final Fantasy, or have the same cast but no continuous plot, like Mario. The only series I can think of that comes close to a continuous cast and plot are Ys, which keeps the same protagonist and best friend but has almost no other returning characters; Trails, which keeps the same setting but the protagonist and party members change often; and Metal Gear, which has ended.
Kingdom Hearts is an outlier in this regard. If you want a story focused video game series with the same cast and plot that spans twenty years, then Kingdom Hearts is your best and probably only choice. Now I don't actually like to read those books and comics that span twenty years because I find them repetitive, but Kingdom Hearts doesn't have this problem because the gameplay changes significantly from game to game. The first is focused on platforming with hack and slash, then it's a card game, then it's a character action, then a few games here are just movies, there's one with monster collecting, etc. It's varied and unique.
Another draw to this series is the Disney characters and worlds. Again, I don't actually care much for Disney movies, but I love them here because of the variety. One world might be in a whale, another in a computer, one is underwater, in one you sail a boat, etc. While there's a core cast that is recurring there's tons of Disney characters to add variety to the story and the aesthetic.
Is Kingdom Hearts always good? No. There are a lot of things I dislike. Some games I don't like the combat, some characters I don't care for, some worlds overstay their welcome, etc. but this is really about being more than the sum of its parts. If I had to rate each game in the series and average them out, I'd probably end up with a 7.5/10, but as a whole package, being an incredibly unique media experience that you won't find anywhere else, it has to be a 10/10.
Kingdom Hearts is an outlier in this regard. If you want a story focused video game series with the same cast and plot that spans twenty years, then Kingdom Hearts is your best and probably only choice. Now I don't actually like to read those books and comics that span twenty years because I find them repetitive, but Kingdom Hearts doesn't have this problem because the gameplay changes significantly from game to game. The first is focused on platforming with hack and slash, then it's a card game, then it's a character action, then a few games here are just movies, there's one with monster collecting, etc. It's varied and unique.
Another draw to this series is the Disney characters and worlds. Again, I don't actually care much for Disney movies, but I love them here because of the variety. One world might be in a whale, another in a computer, one is underwater, in one you sail a boat, etc. While there's a core cast that is recurring there's tons of Disney characters to add variety to the story and the aesthetic.
Is Kingdom Hearts always good? No. There are a lot of things I dislike. Some games I don't like the combat, some characters I don't care for, some worlds overstay their welcome, etc. but this is really about being more than the sum of its parts. If I had to rate each game in the series and average them out, I'd probably end up with a 7.5/10, but as a whole package, being an incredibly unique media experience that you won't find anywhere else, it has to be a 10/10.