Thanks go out to:
The SDA crew (too many of you to list now) - keeping SDA awesome!

00greenbean00, becored - Other people run this game now! The competition drove these times down really quickly - in one three day period each of us set a new record!
vlackSR - Doesn't actually run this game, but deserves credit for finding the real time method to do the zips which brought the time down significantly!

If you want to learn to run this game, I've created a guide here: https://kb.speeddemosarchive.com/Wario_Land_4

So, what's changed since last time? Well, you can zip now, that's a thing. Basically the way this works is you find a 4 or 5 tile high ceiling, jump into the corner of it, ground pound just before you hit the ceiling and pause. If you see Wario's hat kind of embedded in the ceiling, then when you unpause, hold away from the wall and press A, and you should move into the wall and upwards. Zipping is that easy!
However, when you want to change direction, you have to pull off -another- frame perfect maneuvre (jump then change direction the next frame) and you can't let go of both left and right for a single frame. So I pause to do this as well but often you do this in positions where you can't see any visual indicator of a jump, so you have to listen for the jump sound, which can often be hard to hear against the music. It's pretty messy overall. So any run that gets out of Pinball Zone (where you have to do two zips with a total of four direction changes) is a miraculous occurence.

Some general things about this game: Apart from the Entry and Golden passages, the remaining passages can be done in any order. With the recent finds in this game, all of the runners do Ruby first, and then anticlockwise - even though it wastes a couple of seconds on the map, the zips in Ruby are real run killers, as they can softlock the game, and being able to reset after failing them is much easier when you only have to throw away ten minutes of work rather than 30-40.

In each level, the objective is to pick up four pieces of gem (in the yellow chests), the key, and hit the frog switch to open up the vortex at the start of the stage.

Also, movement techniques are interesting. Horizontally, your fastest means of movement is holding R to dash (though B-punching and jumping accelerates quicker), however if you're at dash speed any jump you do is full-size. So often what I'll do before jumps is let go of R and very quickly jump - you don't go straight back down to normal running speed so you can preserve most of your velocity, then hold R as you land to return to dashing.

Vertically, Wario's typical jump height is 3 tiles, but by using an enemy you can get a jump height of four, or even more tiles if you're clever!

Finally, this game has what I like to call "loose jumping", where if you hold jump before you land on a platform, you'll jump on the first available frame. As far as I can tell you still have to be kind of close, but there's enough leeway to make things like preserving dash momentum pretty straightforward.

On to the run itself!

Hall of Hieroglyphs: Even this level has some new stuff! You'll notice some quick dashjumps in small corridors to build speed, and a rock used as an enemy to bounce up and skip a ladder. This was a below average start though.

Spoiled Rotten: Change of tactics here too, attacking from the right side works out faster since you don't have to wait for him to move out of the corner for the last few hits.

The Curious Factory: Main change here is going across the top of the platforming room in the runback. It only works out about three seconds faster, which is less than I was expecting, but I took the time to learn the jump timings and they're really consistent now.

The Toxic Landfill: Skipping Fat Wario in the second room saved substantial time (around five seconds) and proved to be quite simple. Other than that, and killing an enemy with the same shoulder charge as breaking a green block (the timing on that is much tighter than it looks), this stage is pretty straightforward.

40 Below Fridge: First two zips in this level. The first is simple, once you hit the right frame simply hold up-right and A after unpausing (the up is so you'll grab the ladder). Hit this one at the first attempt. Without anything else going on this looks a bit slow, but what I'm actually doing is changing my grip on my GBA. I use a classic GBA, and when doing zips my right hand presses both A and Start - covering quite the distance.
Second zip is right after the frog switch. Again, got in to this one at the first attempt! The pause in the middle of it is to change directions, something that also needs quite some precision. In this wall, you do four jumps while holding left, a fifth just before pausing, then switch to right after the pause and seven more jumps holding right. Then you should be above the screen like this. (You'll actually see Wario appear below the screen at times, this is just so much further above the screen that the game doesn't really know what to do.)
While off screen you can't just hold left to exit - once you see the brown block near the CD you need to jump to clear the gap you would normally enter this screen through at the start of the stage. Then once past that gap you need to keep jumping until you hit the correct gap (at the top of the ladder) to reach the vortex.

Pinball Zone: Follows the same track until hitting the frog switch. Then the last two rooms are skipped through difficult zips.
The first zip requires you to change direction three times. The inputs are as follows: hold right, jump once, jump again and pause, switch to left, jump once, jump again and pause, switch to right, jump again and pause, switch to left, and jump three times to escape. I messed up the last direction change a couple of times, which is why I paused quite a bit. Still, 2nd attempt on the entry was very good.
The second zip is one jump while holding left, a second jump and pause, switch to right, and jump twice to exit. Hit this at the first attempt too, meaning I'd lost almost no time to zips in the entire Ruby Passage!

Cuckoo Condor: Still the easiest fight in the game. I dropped the first egg, though, and had to save the fight with immediate throws out of the air.

Toy Block Tower: This stage has a very interesting zip. It requires a change in direction but it seems harder to pause buffer the change in direction. I have done it before, but on this occasion it failed me and I just fell to the other side. Here I have to be very careful: I have to break the lower block to get back in position and attempt the zip again, but if I break the higher block as well I can't do the zip at all and the run is over. Overall this zip takes me 6 attempts, plus the time taken to get back to the zip point. It still works out faster, though - this is the single largest time saver in the game.

The Big Board: Largest time saver here is in the goal room: instead of waiting for the dice to roll back around to 6, you can ground pound after hitting the dice, making you accelerate faster down to the ground and just giving you enough time to jump and hit it again before it turns to 1. The ideal route gets four 6s in a row this way, and I succeeded! You also use this method to get a 2 towards the end to turn the red blocks off, which makes the runback slightly faster.
Made a silly mistake near the end where I forgot what room I was in, but otherwise this went really well, and got my best escape time of 2:15.

Doodle Woods: Only thing I'd change is that, in the ideal case, you cross the long horizontal room in the runback without losing speed. I botched one of the jumps for that though.

Domino Row: New damage boost in the last domino room, saving a couple of seconds due to being able to go through a set of spikes.
The underground section looks like a prime candidate for a zip, but unfortunately not - zips don't work on three-tile high ceilings. In theory you could use a zip to get back to the pipe but you'd have to hit that one first go to save time with it.

Aerodent: Unfortunately, all the precise play in the first half of the game counts for nothing if you mess up even slightly here. I made the cardinal error of holding R during the attack phase, and when attempting to turn around I skidded instead, giving the mouse time to retreat and forcing another phase. That by itself cost about 15 seconds, but considering the fight was already bad, I could have picked up as much as 30 here...
Then followed up with a map error. My brain's pretty scrambled at this point...

Crescent Moon Village: Missed a roll cancel here, just to demonstrate how much time they save. Obviously that's why.
Letting the ghost grab the key at that one point in the runback is intentional - he always moves into a convenient spot for you to pick it back up without losing time.

Arabian Night: This is the last zip that requires a change in direction. I got the activation first try but missed the jump to stay in the wall, so I only saved half the time I could have. Ideally this zip goes back to the left and straight to the key.
Second zip in this stage only took two tries as well. They're really harder than this, I promise!

Fiery Cavern: Took an extra hit early on, had to slow down and wait for one of the lava geysers later to compensate.
Having already blown a run in a similar position due to getting hit by an icicle in the runback, I elected to take both hearts on offer in the final fire area. Naturally, the extra wasn't required.
Also made a pretty bad mistake at 4:16 on the runback timer costing 4-5 seconds.

Hotel Horror: Not too much notable here besides the only use of an enemy throw off a large enemy in any category of this game. And I got it first try!

Catbat: There is an alternative strategy you can use in this fight, where you dash jump off the ground to hit the first phase as he creates a wave - at his low point he is just low enough to hit. It's very precise, though, and hitting him too early costs about 6 seconds as he gets knocked back quite a distance. So I took the easy way out and stuck with the safe method.

Palm Tree Paradise: I believe collecting the second gem piece is faster on the way in than on the way out. I'm positive collecting the third on the way in is faster because your shoulder charge is at the perfect speed after exiting that room to hit the gap ahead without losing speed.
The bounce off the monkey up to the key is new to this run - although unfortunately, in this case I did it too well and cleared the block I was meant to land on!

Wildflower Fields: Last zip in the game, only took two attempts! Can't complain with my zip execution at all.

Mystic Lake: Something happened in this stage that I'd never seen before - I got caught by the second bubble but was far enough underneath the overhang that it popped straight away! I didn't feel like tempting fate after that so I took the last two quite safely.

Monsoon Jungle: This has gone from a moderately comfortable level to an absolute nightmare. This provides perhaps the best example of how slick movement in this game is when controlled right. I took a couple of the jumps safe by resorting to B-dashes after I'd lost some momentum but I didn't fall in the water once!
That is, until attempting to reach the vortex...

Cractus: ONE two three ONE two three ONE two three...

Golden Passage: Lost three seconds fighting the current in the underwater section.
The fact that the base of a chest acts as a platform for a short time has been known for quite a while, but shoutouts to Dangerless for figuring out you can use it to skip dropping back into the water in the key room!

Golden Diva: Where did this fight go so wrong? Actually, the biggest mistake I made was getting the first hit with the green ball too fast! Golden Diva's sweeps all take the exact same amount of horizontal space (about 90% of the screen width) meaning she always moves to the same position if you hit her in the same spot. I had a plan to get the first three hits a certain way (that made the first hit with the hammer very easy) but after missing the green ball as it dropped I ended up being able to get the hit early. Big mistake! This put the hammer in a really bad position to start and the fight just got worse from there (including missing a hit with 4:47 on the timer that I thought I had in the bag!).
My time here was 1:38, my best fight is 1:20. Considering I had to wing it for the entire fight, though, I'm not too upset with how that went.

Thanks go out to:
The SDA crew (too many of you to list now) - keeping SDA awesome!

yoshifan - probably the biggest contributor to this run as far as strats go. I did exactly one race on Normal with him where he lost by half an hour, but in the time I was able to watch his stream after finishing I picked up three new level strategies from that alone! He also had a few others recorded that helped me out too.
andymac, SuperHappy, JuanValdez - After doing my own initial route planning I watched all three TASes of this game. None of these are on S-Hard, so the room strategies are vastly different, but I learned a lot about general movement techniques from them.
Finja - popped up on the forum with a couple of handy tips for levels.
My stream viewers - for the support! I had no idea if this would be a good watch before I started running it, but the fact that I consistently drew viewers tells me it was. :)

After I finished my Normal run I moved on to Hard, and finally this. (I elected not to submit the Hard run as it's a bit of a middle-ground as far as categories go...) Here's what changes between categories:
* Start with 1 health in regular levels (down from 4)
* Start with 4 health in boss levels (down from 8)
* Most chest locations, and some key locations change (mostly to more out-of-the-way locations)
* More enemies, and they're more dangerous (eg. spear men will start as red)

In particular, starting with 1 health makes this category INCREDIBLY difficult, so I'm very pleased that I was able to get a deathless run. This is the only deathless run I've managed, and likely it'll stay that way, at least until some competition rolls around.

Some general things about this game: Apart from the Entry and Golden passages, the remaining passages can be done in any order. Only two orders make any sense though: doing Emerald around to Sapphire, or the other way around, because any other order would lose time on the map. So I do Sapphire first and go around in reverse order, since Sapphire has the hardest levels to optimise in it, and I'm better off resetting after five minutes than after fifty.

In each level, the objective is to pick up four pieces of gem (in the yellow chests), the key, and hit the frog switch to open up the vortex at the start of the stage.

Also, movement techniques are interesting. Horizontally, your fastest means of movement is holding R to dash (though B-punching and jumping accelerates quicker), however if you're at dash speed any jump you do is full-size. So often what I'll do before jumps is let go of R and very quickly jump - you don't go straight back down to normal running speed so you can preserve most of your velocity, then hold R as you land to return to dashing.

Vertically, Wario's typical jump height is 3 tiles, but by using an enemy you can get a jump height of four, or even more tiles if you're clever!

Finally, this game has what I like to call "loose jumping", where if you hold jump before you land on a platform, you'll jump on the first available frame. As far as I can tell you still have to be kind of close, but there's enough leeway to make things like preserving dash momentum pretty straightforward.

On to the run itself!

First thing you'll notice is the speedrun resets in this game a LOT. The game saves automatically at the end of each level or boss, and it's quicker to go through file select than to wait the cutscenes out. In all, I use 30 resets to save over 11 minutes of otherwise wasted time.

Hall of Hieroglyphs: So instantly we have a time limit, and red spear guys EVERYWHERE. This level is all about really precisely placed jumps to get around all of said spear guys (there's only one heart on the route, so you can't take a hit until the very end).

Spoiled Rotten: Standard fight, apart from missing the ground pound on the second enemy which cost about half a second.

Crescent Moon Village: This is a ridiculously hard stage to do on one heart! It starts with the opening room, where you have to hit all of these enemies a certain way - I need to wait for the one on the second platform to turn around, then they all fall into place nicely.
It is possible to pick up a few more hearts by getting zombified in the first room and swimming for a while, but it takes 15 seconds to get those hearts, and they don't get you back that much time. So this, while looking bad and being much harder to play, is in fact the fastest way.
As in Normal, I allow the ghost to take the key off me once in the runback - I lose a second or so waiting for it but have no consistent way to make the roll beforehand without losing the key anyway!

Arabian Night: Pretty standard aside from the fact that the shortcut I use in Normal is blocked off in S-Hard by even more enemies.

Fiery Cavern: Slightly less use of damage invulnerability in this level than on Normal. I actually have to think about what hits I take this time!
In the frog switch room, I ground pound twice because if I only do one, the enemy next to the switch throws a rock at me, forcing me to either take another hit or wait. Unfortunately, as he's facing left instead of right, I have to wait anyway, and let the ice shot pass over my head.

Hotel Horror: This is basically enemy throws: the stage. I use one to go up the outside of the stage instead of up level 3, and another to skip Fat Wario in the frog switch room.
This level also features what is comfortably the worst mistake in the run: you're supposed to simply fall alongside the far left block and land on the chest, but for reasons known only to me I hit left and missed it. That mistake alone cost me about 40 seconds. Why I didn't reset for it, I have no idea.

Catbat: Once you deal enough hits to the bat to make it disappear, you can actually chain all the hits in the entire second phase of the fight. Simply keep ground pounding on the cat's head. Importantly, each time you land on the cat's head you should release down and press it again, even on the hits that don't count! If you don't, you just get pushed off to one side.
This is a virtually perfect fight, and has a ten-second margin for error as far as keeping all three chests into the final battle. It would be impossible without the hit-chaining trick on the second phase.

Toy Block Tower: When holding large objects like the triangles, you move much faster while jumping than just walking along the ground.
Made a mistake by going into a door early. A habit I had to train out of myself while doing this run was that when switching between left and right, I tend to roll my thumb across up on the way - a habit I picked up from Sonic since up almost always does nothing in that. Here it sends me through doors when I don't want it to.
Unlike in the older Wario Land games, the trigger for Fire Wario to switch between running and burning form is simply hitting three walls, so I try and make the distance as short as possible.

The Big Board: After running this game for a while I've come to the conclusion that I have absolutely no idea what the best way of handling the board is. In Normal I save all my slot rolling for the end and it's at least consistent, but when learning Hard and S-Hard I got times that didn't feel consistent with my level of play when switching between doing most of the board during the stage or at the end.
Normally I have an order for how I handle the board so I'm at least ready for what's coming next, but I messed it up somewhere and instead of rolling a bunch of 6s in the goal room, you see me roll quite a few 4s just to stay away from lightnings and Warios (Wario in the goal room turns you into fire, which incidentally is why I'm always facing left when hitting the dice). Unfortunately, this was the one other really poor stage in the run.

Doodle Woods: Positioning the pig is super important to making sure you can get an enemy bounce up to the gem in the top right of the frog switch room. That enemy tried to get his words in though!
The jumps as Fat Wario are surprisingly tricky: you actually want to neutral jump and then move just to make sure you don't run off the edge of the platform you're standing on.
At the top of that same room, you normally need to hit the pencils five separate times (to reach the top one, then to get the key, then to get out) but clever enemy throws mean you need precisely zero of those hits!

Domino Row: If you jump off one of the domino switches just as you land on it, you actually get an extra tile's worth of height in your jump. This saves time in two rooms. Other than that, pretty straightforward stage.

Aerodent: This boss is AWFUL to optimise. I worked out how the TAS was able to defeat him in a single round: basically any time you touch the bear from underneath it will float upwards, so the trick is to land damage on the mouse without hitting the bear at all. This requires VERY precise positioning, and Aerodent is a 16-hit boss. There are two different heights that the game will still let you get hits on, so you can miss once... but you have to do it 14 times correctly, not an easy thing to do.
I was able to get into a rhythm where I'd move away for a certain length of time and I'd be able to get chains going pretty consistently, but every so often I'd mess it up just a little and he'd fly away again. You'll notice that typically I attack from the side he's moving towards, this increases your margin for error, but only slightly.
Got a two-cycle fight here, which is still pretty difficult. However, as you can see, having to complete an entire second cycle takes quite a bit of time - I lost about 10 seconds versus a one round kill.

The Curious Factory: First room of this stage is a serious run-killer. I play it pretty safe here.
If you thought the spinning platform rooms were intense before, now they have birds in them too! All of the jumps are very tight to avoid damage, and I only have two hits to play with.
yoshifan pointed out to me how the crushers work: they'll only start their cycle if they're within range of the screen, so standing away from them won't cause them to start crushing. I modified his strategy slightly, throwing in a ground pound so I could clear away the enemies quickly. Normally it takes a while to get a pattern where you can get through the two crushers up ahead without either of them hitting you, and as the next two rooms indicate, getting crushed costs a LOT of time (around 20 seconds!).

The Toxic Landfill: Going into the door here was a compound error. As well as wasting time in and of itself it also wasted my invincibility frames from untransforming, so I had to play very safe while collecting the first chest. Then I screwed up the next room too and got another Fat Wario transformation. :/
To make up for it, this stage does have the best room strat in the entire game: in the room with the top-left gem, the game expects you to turn into Fat Wario and knock the spring enemy down for it to bounce you up to the top. Instead, I take the floor out from under the spring enemy and skip all the intermediate steps!
Thanks to Finja for pointing out the shortcut in the runback! Not only does it save time in and of itself, it actually despawns one of the enemies at the top, giving you a clear run at the green block up ahead!

40 Below Fridge: Every single enemy in this stage is capable of killing you, so I deliberately use a lot of ground pounds to reset their state to one that I can kill easily.
The cylindrical room is extremely difficult to optimise in S-Hard: there's ice shooting enemies everywhere as well as icicles on the ceiling in line with where you need to jump up to the very top.
Getting ice blasted or covered in snow in the runback costs a LOT of time, so I went out of my way to take some damage which prevents me from being afflicted by other statuses.

Pinball Zone: Full health takes time to get, but is absolutely mandatory. There's no way you're getting through this whole stage without taking damage.
Lost a bunch of time in this stage, which is almost to be expected. This level is HARD. The second room was entirely my fault, sure, but I got really unlucky with the ice shooters in the fourth room. Not sure how I didn't hit the first one...

Cuckoo Condor: Perfect fight. Easiest in the game.

Palm Tree Paradise: This level, like Hall of Hieroglyphs, throws you for a loop on S-Hard and puts the frog switch at the very start, forcing you to play the entire level on a time limit. What this means for the speedrunner is simply that you have a timer for the whole level instead of just half of it... which is actually quite nice.
In S-Hard this level has red spear-men EVERYWHERE, it's definitely not anywhere near as free as it is in the lower difficulties. Unfortunately I was caught by a monkey turning me Fat Wario again, costing multiple seconds.

Wildflower Fields: Was trying for an enemy throw here but got trolled by the bee: this enemy throw is only a one-shot too, since after using it it touches another enemy, killing them both (which is intentional, otherwise they're in your way on the way out of this room).
The enemy throw in the following room is about even on Normal if you get it first try, but works out faster in S-Hard because of all the other enemies you'd have to dodge on the way up. To make matters worse, it's actually possible for this enemy to block a super ground pound from the upper level and you have no way of seeing it in time.

Mystic Lake: Made it past the first two bubbles in the narrow water channels, and didn't attempt the third due to missing one of my swims.

Monsoon Jungle: Reaching the first heart in this stage is the most relieving feeling because it means that the run will finish. The last great danger in this run is dying before getting that heart, typically to the second crocodile on the second screen.

Cractus: ONE two three ONE two three ONE two three... 100% rhythm. Again, thanks to yoshifan for reminding me this works.

Golden Passage: Another yoshifan strat here, fighting the current puts you a long way ahead in the stage, saving a ton of time, probably about 30 seconds all told. This is also the one stage that doesn't change at all between difficulties... and also technically is treated as a boss stage, at least in terms of your health.
In the end I use less than half of the S-Hard time limit!

Golden Diva: This is almost exactly the same as Normal, the only real difference is you have to be more watchful of your health if you get too many green ball attacks.
The key speed strategy is hanging on to the hammer as long as you can, so that you can get lots of hits in quick succession. I screwed it up towards the end, if I'd managed two more spring hits I would have saved quite a bit of time. That said, 1:38 is still a very acceptable fight.

I did say that I would submit the first deathless run of this game that I got, and I was true to my word. :P
However, I'm not entirely happy with it, the mistake in Hotel Horror in particular makes me cringe. I did make attempts at this after getting this run and wasn't able to get anything close to this, so for now this will have to do. Unless, as I mentioned, some competition appears, in which case I might have to defend this record...

Enjoy the run!