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.
Ear Worm: Pretty much the entire soundtrack, some of which includes Sampling of the iconic arcade tunes.
The soundtrack for the level Far Out is considered by some to be the best soundtrack in the game, with its ethereal use of synth pads and catchy chord progressions.
Porting Disaster: While it's understandable that the Game Boy Advance version wouldn't have everything from its Playstation counterpart, many seem to agree that they could have retained more content from it, since several levels are removed, and only one boss remains. It's not unplayable, but it still could have been better.
So Okay, It's Average: The general consensus seems to be that, while nowhere near the levels of Super Mario 64, Pac-Man's jump to 3D fared much better than the majority of classic 2D characters.
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.
Anubis Rex gets extra special mention: the devs admit they ran out of time to finish playtesting him, leading to some serious Hitbox Dissonance.
That One Level: Spin Dizzy. It's really long, the checkpoints are few and far between, and it's full of bottomless pits that are easy to fall into because of both moving platforms and difficulty in knowing where you're landing after a jump.
Pac-Man World 2 contains examples of:
Author's Saving Throw: As stated on the main page, the original releases of the game prior to the best-seller re-releases were much more difficult (ghosts were One-Hit Kill, power-ups wore off more quickly, and the level design was much meaner). Apparently, Namco got quite a few complaints about this, which led them to lower the difficulty significantly in subsequent releases, resulting in this trope. For instance, one example — in B-Doing Woods, the first level where you see B-Doings (a completely new mechanic), they added a safety net below the first set to help players get used to the new mechanics before moving on.
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.
Most Annoying Sound: Do we really need to hear that Hanna-Barbera ricochet sound every single time you Rev Roll? Well, good luck on your adventure, because you'll end up having to hear it often in sections where you have to perform constant Rev Rolls. The sequel is also guilty of this for the same reason.
Nightmare Fuel: Pinkys entire demeanor plays her out to be an unhinged Yandere. How so? In the opening cutscene, Pinky stands outside of Pac-Man's window as he sleeps picking petals off a flower and flees when Pac-Mans dog starts barking at her. During her boss fight, she makes "If I Can't Have You..." declarations. Even her boss theme becomes unhinged after a few discordant notes, and only gets more psychotic and discordant as the song goes on.
That One Boss: The battle "Clyde in the Caldera" against Clyde. Ask anyone who has played this game what the hardest boss is, they'll choose Clyde without a doubt. He Lampshades it by claiming he doesn't think even Spooky can take on Pac-Man. He is basically Pinky turned Up to Eleven with a lot more attack force and smaller platforms with all the bridges taken away. Coupled with the utterly despair filled boss theme, you'll soon realize you're utterly doomed before the fight even starts.
In addition, rev-rolling was the attack you used to defeat Pinky, but Clyde's mech is invulnerable to it. Instead, you have to butt-bounce his cockpit when he temporarily flies down below ground level and stops shooting. 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 - when he's down to four hits left, you'll more or less resort to butt-bouncing over and over and over just BEGGING to find the sweet spot. 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; the positioning of midair pac dots was very clearly not playtested.
Haunted Boardwalk might qualify for the worst level to 100%. The first three parts (the beginning, the first set of sinking boards, and the second "stable" line) aren't too bad, but when you hit the last section, get ready to throw your controller at your screen five hundred times over. For starters, there's several crates they stick which can often lead to your death just because of what direction the board decides to sink in, turning it into a halfway Luck-Based Mission. Then there's the fact that the path splits into two twice, one of which where the "right" path (with a Pac-Dot chain) is way off in the distance and easy to miss, and at the very end no less! Oh, and the worst part? Somebody on the dev team decided to put Pac-Dot arcs in the last section... no fewer than THREE! If you miss even one of the dots in the arc, you have to kill yourself and start over, and it's going to happen a lot. In past levels with arcs you could at least go back and get any that you missed, but because of the sinking boards, there is no way to do this. Oh, and if you have the version of the game where the ghosts kill you in one hit, good. Luck. The level is littered with ghosts in some very mean places, and they even finish with three of them coming straight at you. Thankfully the later version (Greatest Hits, Platinum Hits, and Player's Choice across the consoles) nerfed them to only slice one hit point.
Pac-Man World 3 contains examples of:
Broken Base: Depending on who you ask, this is either the best game in the series, or the worst game in the series.
Pac-Man talking. Some fans are fine with him talking, others aren't.
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.
Hilarious in Hindsight: The 25th Anniversary trophies of Pac-Man look exactly like his amiibo in pose. Bonus points that the silver color and red base are so similar to Silver Mario's amiibo.
Nightmare Fuel: Some textures in Banni Canyon — only Banni Canyon, none of the other levels — can glitch out, flickering between normal textures to misplaced scenery textures to Missingno-esque static to eyes.
Vindicated by History: Downplayed, The game is still as divisive as ever but the voice acting aspect has been more appreciated in later years for its professional talent and writing, even by the game's detractors as opposed to back when the game was first released where the mere idea of Pac-Man talking being controversial and rubbed people the wrong way. Martin T. Sherman now even quite possibly now rivals Marty Ingels in terms of popularity for Pac-Man's voice.
That One Level: The Spectral Realm levels are typically not very fondly remembered. It doesn't help that they are home to the most Spectral Monster chases.