Out of curiosity, for those who played through Donkey Kong 64, what part of the game is the most commonly agreed upon element that they find frustrating? I'm asking like mechanics, minigames, certain collectibles, worlds, etc. I'm asking this, because so far in my first ever playthrough, which has been mostly blind and without any sort of outside help, there hasn't been anything that bad that makes me not want to continue it at all.
You have to do the mechanical fish when you first reach Gloomy Galleon, because an ammo upgrade later on makes it nearly impossible. Beaver Bother is terrible, so is the slot machine minigame, and the top down one with the mine carts can also get brutal. The thing with the minigames is that they're all repeated at least two or three times and get much harder as the game goes on, so if you beat it once and think "that wasn't so bad", it's probably going to get worse. The beetle is fairly infamous, but the Fungi Forest rabbit race is even worse, I think you basically have to rely on him getting stuck on something to actually win the second one. I think the thing I spent the most time on was actually DK Arcade though, I remember the second round being incredibly hard (and this one is required to beat the game).
DK64's reputation is really not primarily because of its awful/broken parts though. They sure don't help, but it's more just the general tedium and nothingness of the game that breaks people. It's infamous for how much stuff it has to collect, but the other part people don't really talk about is how little game
there is attached to that stuff. It's on the exact opposite end of the spectrum from Banjo-Tooie, which has extremely elaborate scenarios for a smaller number of collectibles than the first one. There is occasionally an actual objective here that isn't a bad minigame, like flying through rings with Diddy's jetpack (this is another potentially really hard part, if you're not used to the jetpack in Pilotwings this has a steep learning curve). But they are not where you're going to be spending most of your playtime. It feels like at least 80% if not more of the game is basically just walking around hitting switches and picking up fruit. Generally the switch will open a door, and out comes a banana or a minigame that gives you a banana.
It's not a platformer, you can barely jump up a staircase or walk in a straight line, and there are very few challenges related to climbing anything. It's not a shooter, most of the time the guns are just for hitting stationary switches, and there are again very few instances where they actually test your aim. Most abilities follow suit. It's not like Banjo-Kazooie where you get the ability to become invincible and you can do it anywhere, in this one you get the ability for only Donkey Kong to use a barrel you can find that will turn him invincible for a short time so he can walk to a specific location once. It's not like Banjo-Kazooie where you get the ability to ground pound and then the same basic action is used in a bunch of different contexts for smashing wood huts or making a turtle retract his feet, in this one you get the ability to press switches, which can be color-coded based on level of ground pound you possess and face-coded so that only a specific character is allowed to press them. When Diddy gets a new headbutt move, it is for hitting switches and only
that. You could replace most of the abilities in this game with keys and it would be fundamentally the same game. It's like they removed all of the actual game mechanics and all of the layers of abstraction that would make it a video game in favor of setting these apes loose in a Skinner Box.
This is why the so-called "lock and key design" in games like Zelda and Metroid is really special. I find that most metroidvanias and Zelda-likes put very little emphasis on this or miss the point entirely. The bow in Ocarina of Time is not a key, it's a toy. An entire game mechanic unto itself. You can master using it, there are specific challenges testing how good you are at using the bow. Missiles don't just open red doors, they're an extremely important weapon. Taking the care to both fulfill the "action" side of action adventure by making using the item a skill, and to work these items into the fabric of the world itself by having Link shoot eyeballs or targets instead of a toupee off a man's head or a button with a picture of a bow on it is what separates Zelda from Jungle Japes or an inane adventure game puzzle where you have to find the one specific use for tape that the developers thought would be funny.
Lastly, a lot of people will go on about the tedium of the character switching in DK64, but in my experience planning my moves to get as much as possible in one go and set things up for the next character was actually the most
interesting part of the game, even though it's hard to say if this was even an intended part of the gameplay loop or if the entire color-coding concept was thoughtless padding from beginning to end. I mean, if there's one thing I can compliment the game on, it sometimes has a nice atmosphere with the music and fancy lighting effects, so just walking around picking things up while thinking about where you'll go next can really be kind of zen. Or maybe that was just my brain trying to cope after playing hours of DK64.