Any of the levels in Superman 64..

Pretty much all of the regions of Dark Aether, except the Dark Temple Grounds and Sky Temple. Dark Agon Wastes is admittedly not too bad, but the Dark Torvus Bog and Ing Hive make me reluctant to complete Echoes a second time.

Ghost Houses are the worst though. At most, there should only be one or two in a Mario game. There's much more pleasant ways of showcasing a haunted level theme than sticking them into Ghost Houses. I think the only Ghost House-esque level I've actually really enjoyed is Big Boo's Haunt in SM64/DS.

omg the same thing always happens to me im always missing a small key -.- and i have to check my map and go all over to get it <.<

Woah. I agree on all of them. Especially that chameleon. I still can't figure it out.

Most water levels for me. Some do it right, like Majora's Mask and Mega Man games, but pretty much all of them just aren't as fun. Just look at Star Fox 64.

All the levels in Super Mario Sunshine, that they take FLUDD away from you. It always takes me a long time to pass them >

Well I'm better than what I was when little MadAussie first burst onto the gaming bloody scene but the dreaded ice levels and strict time countdown sections in every platformer from the 80's + 90's helped shape my unique madness to a fine precision... When a stage like this hits my screen I will be droppin' F bombs enough to make NWA tell me to calm down

Super mario bros.- Pretty much any levels with the hammer bros. but particularly 8-3 Those little bastards!

Looks like someone never played The Lost Levels. lol

Oh yeah, and this level, another water-themed level. Not that the level itself is really difficult or anything... I just REALLY hate the jet ski levels in that game, and this was the worst one of them. NTSC players were lucky that their Platinum requirement was so forgiving.
Hang'em High was also pretty bad... I never got a Platinum Relic in that one as a kid...
I have the game <finally> shipping over to me along with the other two, so I'm feeling a bit nostalgic about it and looking back on all the old levels I hated. I haven't played it for years though.

I forgot to mention every single ice level that was ever created.

@Harmo: I don't think I want to do that..
@Starman: That music is really awesome, bleh, makes me sad that I never played a Mother game..

The Ghost Houses in New Super Mario Bros. U are very tricky the first time you play them, but they're not bad once you play through them again and know where to go. The ones in Super Mario 3D Land were pretty easy.

Pendulum Castle was the hardest level for me in NSMBU.

any level with water in mario kart. controls get horrible and the race seems to get really slow

The freakin maze in sper smash bros brawl, for the campaign.
For hardest probably any level in ghosts n goblins

the water level (or ice level. take your pick, idiots...)

you do know thats not the original music for that right?

I know, I prefer this over the original.

The prep. work and temple for the Zora Bay in Majora's Mask

Grr, do you know what other levels I love to hate in Warped? The biplane shooting levels. They are just... I don't know if they outdo the jet ski ones for me, but I just don't like them as much as everything else(with the exception of the epic N-Gin boss fight). I'd go so far as to say they're the least fun ones in the game(that said, I did enjoy them still, and I love the game as a whole). Plus, getting Relics on those- just horrible, like with the motorcycle levels(which, on the other hand were likely my favorites!). I can't imagine what playing Crash 1 will be like, because I hear that's the toughest in the trilogy...

That maze level in Shinobi (3DS),I absolutely hate it so much.

It's not really a level, and not even a dangerous place for the most part (although it does have a dungeon inside of it), but the Grand Cathedral in Tales of the Abyss, because it's so darn big (as you can guess by my earlier statement of it having an entire dungeon inside of it).

Seriously, there are loads of intertwined hallways in that place, & every time I visit it, I wander into new areas I haven't seen before (the developers know people will get lost too, because every 3 or so rooms you'll come across an NPC that's there for the sole purpose of bringing you back to the building's entrance should you become lost).

The dungeon part of it (essentially the building's basement) isn't nearly as confusing as the rest of the building, and there's really no reason why the place is so big (or at least no reason why you're given so much access to it). There are a few sidequests that task you with finding something in the building, but they never take you very deep into it.