Advanced Extra 5, AKA Polar Large. It's Polar (Advanced 30, the one with all the tiny moving platforms), except harder. While A30 could be quickly cleared with the right timing, that luxury has been removed through the addition of a segment so big that it might as well be its own level. The very last platform goes all the way around, but it's constantly flipping, so if you don't cross in exactly the right spot, you will fall to your death.
Advanced 21 and Expert 36 are two variants of the same level, both involving a track that bumpers move along in a figure-eight. To progress, you have to get in between two bumpers as they come and keep the timing up to get through to the end. A21 actually isn't so bad, but in E36, the bumpers move so fast that you practically need to be running in order to even get on, let alone get through the level!
Expert 7, also known as Exam-C. It's like Advanced 17, but way worse, with the addition of an infamous narrow hill, the first occurrence of platforms that must be traversed diagonally, and a final long, curvy path that's only half as wide as your ball. It's hard to even get to the winding section without taking your time, but if you don't have at least 30 seconds left when you reach it, good luck making it to the goal in time.
Tracks (Expert 9). All of the paths to the goal are skinny and curved, with the shorter paths being thinner. There is a way to bypass it all but it's arguably even harder to pull off.
Stamina Master, also known as Master 3. Got the Infinite Continues unlocked? No? You need them here. It's arguably three difficult levels in one. Here are twotakes on completing it.
Bridge Master (Master 9) consists entirely of a bridge that starts off narrow and gets wire-thin by the end. And it's not a straight path, there's a lot of turns in it. And they aren't curvy turns either; they are 90 degree turns.
Expert 27 is just a breeze, considering its long lines of diagonal moving.
Advanced 15, AKA Floor Bent. The level is a series of hairpin turns each sloped progressively more towards the outside of the level. The other problem is that each turn is also longer than the last one, making each turn exponentially harder.
The second game has "Warp", which is essentially this level taken Up to Eleven. See below.
Super Monkey Ball 2
Launchers has you being pushed by an obstacle, onto a tower that's curved at the bottom, so you can be launched in the air, and then flail your controller stick in vain hoping that the ball will land at the top of the tower. This is one of the earlier weird gimmicky levels that first game shied away from.
Tiers. See Expert 9 in the SMB1 folder? Now picture that if the paths were also tilted and without the alternate route.
Switch Inferno. Pick the right switch out of 30 or so that are all identical or get slammed into a wall! And the correct switch is surrounded by fake switches, so even if you get it right, you may have to go back and do it again anyway.
Not to mention that there is absolutely no indication which switches are correct, so it's trial and error until you find the first one. After that, the correct ones briefly light up.
Pistons. Picture Launchers above, but on a flat surface with massive pistons shooting up out of the ground. The strategy is more or less Trial-and-Error Gameplay; get hit by a piston and hope you land by the goal. An alternative is to stay very still at the central point around six pistons, as there is enough space to fit a monkey in these regions.
Entangled Path. Waiting 20 seconds just for the path to untangle is tedious and then you get barely enough time to gun it, hopefully getting to the goal before the path vanishes. Oddly, the green goal is easier to get on this stage if you know how to get to itnote Follow the path to it once it points at it.
Warp. You have bent floors, the higher (and less slanted) parts of which have bumpers on them to make it harder. There is a green goal by the normal one, but that requires going down a path LOADED with bumpers. You need to be lined up just about perfectly for it.
Labyrinth (renamed Crazy Maze in SMB Deluxe), mainly because getting to the goal is a Guide Dang It affair.
Domes consists entirely of a bunch of tiny, well, domes that make you bounce off at odd angles when you hit them. If you go too fast, you'll simply bounce off the track, and if you go too slow, you'll waste too much time getting over the domes and never make it to the goal. And immediately after this level is...
Amida Lot. The bumpers on this continually move up and down seven narrow tracks, and cross over wherever they can. You'll be pausing the game to get a feel for one bumper's path, and once you get that down, you'll get thrown off by the next bumper over. Where's the goal? On the center track, moving up and down with no correlation to the bumpers. You'll have to get really lucky on timing to pass this, because the tracks are so narrow that you have to be dead center to be able to fit properly on the track. In other words, you have to cross from another track and just hope that another bumper doesn't come. This stage suffers from its basis on a concept that doesn't really translate to other cultures—an amida lot is a children's game in Japan, where its rules are common knowledge, and the bumpers in this stage follow those rules. Without knowing how to play an amida lot, it DOES come down to trial-and-error and brute memorization.
Strata is not so bad in the beginning, but if you're going for the warp you have to cross a very narrow hill at the end.
Spasmodic. Of all the timing puzzles the game has to offer, this one is by far the worst. There are 3 small platforms that are constantly flipping and there isn't much of a window between each flip. If your timing is even a fraction of a second off, you will get thrown off the course.
Helix is a "follow-the-path-downhill" kind of stage — except the entire path is CYLINDRICAL!
For those of you just tuning in, that's the outside of the cylinder. The "inside" isn't there.
Air Hockey of World 9 (or Expert 50) can be pretty hard if you don't know what to do.note Keep going forward, then slow down as soon as you land on the path of one of the pucks.
Hell, any level where there is no indication of the paths of the goal or obstacles. Virtually your only hope of winning is through an exact timing strategy (pausing at certain times and pressing the correct direction on the control stick). Air Hockey,Train Worm,Synchronized... they're all guilty.
Deluxe brings us Catwalk, which consists of three really long, unforgivingly narrow paths. You can bypass those by taking a fourth path that is narrower than all of those combined. Oh, and the widest and narrowest, unlike the other two, lack invisible guardrails to help adjust you.
Dungeon. How about a maze level where the minimap is completely useless?
Spatiotemporal, which consists almost entirely of a giant swinging bridge that never stops moving. Basically, get the timing right or die trying.
Super Monkey Ball Jr.
Please note: given that there are actually a limited number of directions that the monkey ball can face, levels are not NEARLY as hard as in the consoles. That said, there are still some really hard levels.
Master levels, of course, are a miniature hell, this time moreso (bad puns alert) given that the game is miniature in comparison and that these levels take place in a VOLCANO. But Master 4...well...let me explain. Super Monkey Ball levels are tiled. Jr has much larger tiles. In this level, alternating tile colors are alternatively DIAGONALLY SLANTED. You can't stop moving, and there is barely any same ground. Thank god this is the only level with (pick one) that/this (pick both) feature/challenge.
Touch And Roll
Fluctuation (not to be confused with the SMB2 level of the same name, which is vastly different) is Expert 4 from the first game, except harder, especially on the narrow hill at the end.
Palpitation is just your average anticlimax. It's similar to the level Jump Machine from SMB2 except the goal is on a high platform which is moving around the area. Your timing and also landing has to be spot-on if you are to land on this platform.
Freewheeler. It consists of a flat spiral that is constantly rotating. It wouldn't be so bad if the camera wasn't impossible to control; as it is, you do the last part of it going backwards and unable to see where you're going without looking at the minimap.
Pitch and Putt. Good lord. If you don't go as fast as possible at the start, you die. After that, you have to be dead center while flying through the air otherwise you'll miss a platform or even worse, fly over the goal entirely. And god help you if you try and do it without this "super jump". Slanted platforms around holes, with really tiny connecting paths, and some of them are slanted up, making it near-impossible without perfect control over the ball.
Funrun. While it looks like you can just go full-blast and clear it, the very last bumper will throw you off the course if you don't swerve around it. Keep in mind that this is atop a cylinder and if you go too far in either direction, you cannot recover.
From the story mode, we have the Noise Factory Climb mission. The entire mission is played using the Stickyball power-up, and your goal is to roll around on the pipes to redirect the noise flow so you can "drive out the monsters", as the factory worker explains. That doesn't sound too bad, except for the fact that the Stickyball moves very slow while stuck to the pipes, the pipes themselves are also very slow while they're moving, you're given no indications of your progress, the cameraman seems like he's on drugs, and one wrong button push can send you careening down into the abyss for a Fall Out. The worst part of it all? NO MAP.
Banana Blitz presents 10-5, which consists of mostly bumpy surface that makes the result of jumps quite unpredictable, a huge obstacle in a game that requires expert precision. To add insult to injury, all versions aside from the PAL version have a Game-Breaking Bug that makes you fall through the solid platform just before the goal.
Normal 2-7, or Invalid Bowl, and in particular the warp in it. You need to land on and bounce off of a small platform that you can't even see unless you just drop off the starting platform. The warp itself is also on a tiny platform, and it's easy to bounce off of the warp and fall to your doom.