These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Pac-Man World aka: Pac-Man World
Pac-Man World contains examples of:
Demonic Spiders: The bumper cars. To kill them, you have to use a hard-to-control technique to knock them off ledges. Most of the time they keep moving, so you'll inevitably end up falling into the abyss. If you attack them head-on, they'll knock you right back, and they turn in your direction when you get close.
You can also kill them with a Super Pac-Dot Explosion,
Ear Worm: Pretty much the entire soundtrack, some of which includes Sampling of the iconic arcade tunes.
Do forgive us if our fears seem cliché, but the creepy Funhouse world with the walls and walls of distorted, steam-spewing faces will be sure to haunt our dreams for several nights after playing. It certainly doesn't help that these levels are also the biggest time-wasters.
Polished Port: The Game Boy Advance port is damn near identical to the Playstation version
That One Boss: Anubis Rex and King Galaxian. The former for having difficult-to-avoid attacks that pursue Pac-Man while he is taking his time spinning individual platforms over lava to expose its heart, along with the Nightmare Fuel of the first part being chased by a mummy with spike and gate traps galore, and the latter for filling the screen with laser shots in a relatively cramped space while Zerg Rushing Pac-Man with Mooks that fire even more shots and even have shields in the last phase. These are only the second and third bosses respectively out of six.
Oh, and don't forget that the King Galaxian level had a single, easy-to-miss checkpoint. By the way, did I mention this guy has a whole level behind him?
Anubis Rex gets extra special mention: the devs admit they ran out of time to finish playtesting him, leading to some serious Hitbox Dissonance.
Goddamned Bats/Demonic Spiders: Rev Roll Rams. They're intimidating at first when you realize they're immune to your butt-bounce, and no matter where you are they're usually positioned to knock you right into a bottomless pit. Once you know how to kill them — stun them with a rev-roll of your own, then butt-bounce them — you still have to put up with Pac Man's three-second-long "stunned" animation, during which you're completely defenseless.
One final gripe that makes them extra intimidating/annoying: they love to hide in crates.
Good Bad Bugs: If you pause the game repeatedly in the middle of a rev roll, you begin to get this odd levitation that can be very useful. In particular, it's useful for exploiting another glitch in Volcanic Panic — if you first pull this off and then rev roll just when you sink all the way in, you fall through and can skip the entire level. It's hard to pull off, but if you can do it, it makes the time trial a joke. This speed run pulls it off.
That One Boss: The battle "Clyde in the Caldera" against Blinky (called Clyde since Pac-Man Arrangement). Ask anyone who's played this game what the hardest boss is, and with no doubt they'll choose Clyde... err... I mean Blinky. He Lampshades it by claiming he doesn't think even Spooky can take on Pac-Man. He is basically Pinkie turned Up to Eleven with smaller platforms and all the bridges taken away. Coupled with the utterly despair filled boss theme, you'll realized your utterly doomed before the fight starts.
Going further into detail there are two major issues that you need to deal with. First off, his attacks are basically Pinkie's attacks taken to the next level. For example, he shoots smoking-hot rocks at a rate that is about twice the rate that Pinkie shoots snowballs, and the rocks he shoots leave small flames where they land. Should you touch one of these flames, will take damage. Like Pinkie, he will also fly over the platform you are on, but at a much faster rate, and he leaves behind a trail of flames when he does so. Also like Pinkie, he shoots two rocks at a time, but he does it much more frequently; halfway through the battle, he will start shooting three rocks at a time. It doesn't help that he changes his attack pattern after every two hits you inflict on him. The second issue is his defenses. Rev-rolling was the attack you used to defeat Pinkie, but Clyde's mech is invulnerable to it. Instead, you have to butt-bounce his cockpit when he temporarily flies down either next to one of the outer platforms or between the center platfom and an outer one. The issue is in later hits when you can only butt-bounce sections of glass that are not caved in for it to be counted as a hit. These areas are so specific that you need to butt-bounce many times just for a hit. Combine this with his punishing attacks, and you have a boss that certainly qualifies as this trope.
That One Level: A lot of levels compete for this title, namely Avalanche Alley, Blade Mountain, Volcanic Panic, Magma Opus, Haunted Boardwalk, and Nightcrawler. But the king is Ice River Run, combining more Scrappy Mechanics than any other single level (ice physics, giant bears, Rev Roll Rams, picking up power pellets before you can actually see the ghosts), with none of the fun gimmicks like the ice/roller skates.
You could make almost any level That One Level if you're talking 100% completion and Time Trial.
And Ice River Run makes both of those sidequests even worse.
Pac-Man World 3 contains examples of:
Fridge Brilliance: Considering Pac-Man's snarky, sarcastic personality in this game, all the times that he has a big, goofy smile on his face in completely inappropriate situations in the previous games make a lot more sense.