While the show was always aimed at a younger audience, I just remember there being a lot more heartfelt moments back when I was younger, and it felt like a lot of emotion went into it. Maybe it's just nostalgia here, because I feel like the show now, was dumbed-down and its appeal is less widened. Ash, despite all hes been through, is a moron who makes the same mistakes over and over, and every season is like a repeat of the last. It is incredibly kiddish, be it more-so. It's more commercialized in quality, and is really just a show aimed at small children; mostly male.
The Game and Manga (I believe Pokemon Adventures?) have a more serious and more mature tone to them, with death and actual moments of strife. It's not always rainbows and Ash getting yet another Gym Badge. The show itself was made after the original games, and things in the show were just added for filler and aren't considered canon to the game and even the manga. It's why I say they don't mix or cross-over. An example is how Ash is modeled after Red (although a stupid, stubborn, foolish mimic of Red). Ash doesn't exist in the games because he was just made as the protag for the show, and "based" after Red.