So, basically, the hate is because _DK64_ is basically the epitome of the collectathon genre, so it essentially inherits all of peoples' emotions towards the genre as a whole; the game itself is fun, but its idea of longevity is essentially "play every level with every character, and sometimes also find ways to cheat characters into areas they shouldn't be in", as the Diddy-specific collectibles would imply. Also, one specific minigame in particular is memetically impossible to win, because its AI is more advanced than you'd expect from something of its age. Overall, it's a fun game, and takes what Rare did with _Banjo-Kazooie_ and expands on it, but most of the hate comes from people that don't want to play most of it five times.