Retro 1 I did not read/follow the advice title to isolate the last lemming as a worker ! Instead I isolated him with good ol' break your own bridge technique. In the end I have just enough builders to clear.

Retro 2 I tried the 100% here, and had to time carefully the miners to do so. Doable, and some skills left.

Retro 3 That was pretty straightforward, as I am now used to making climbers turn around in miner/basher tunnels. Though at some point I was scared because I thought the climber could also escape to the left, but he can not !

Retro 4 Lead the way with bashers and contain crowd with miners.

Retro 5 Some tricks required but it works in the end. I wondered if 100% was doable, but saving a blocker looking the wrong direction way and standing above a bottomless pit looked too hard to me...

Retro 6 Not a hard level for once. The pickups and layout dictate quite clearly what has to be done. I love the fact that no matter which way the crowd exits the digger pit, one exit is there for them

Retro 7 Now this is masterfully designed, and the clues on where to place the blockers were very welcome ! Thank you Armani.

Retro 8 My first tentative were one basher short as I needed 3. But then by placing the 2 digger pits close to each other, the miner can act as mine+bash, so it works !

Retro 9 Weirdly enough, this one was a quick solve to me ! I saw the solution where the workers have to commit suicide to clear the way quite fast. Maybe my brain was trained after the first 8 levels and I was on Armani's wavelength like JawaJuice would say

Retro 10 This one took some time as possibilities are very large here. In the end I did not use the leftmost part of the level because it used the miner that I could not afford to loose for the rightmost part.
In order to reach the exit with the 2 left entrances, I had to bounce builders on a single blocker, twice but not at the same height. First time I see this in a level, nice idea if this is intended.

Retro 11 For a long time I did not know how to free that top-left blocker without making the crowd splat. Then I used a trick that is also used in the level ONE 4 Falling Steps of my Save One pack : mine a bridge so that lemmings can descend it but not ascend it.
This way I both free the crowd from the splat, and free the blocker with a single miner. Setting this up in this level requires some trials and errors and pixel precise placements of the blocker, last builder and miner though. Not usual as per Armani standard.

Reading other's solution I think this was not intended as people isolate the 4 needed workers with a blocker sooner, then use a trick to turn the miner around.
I think my solution is acceptable too, and remember that Armani was one of the few, if not the only, player who found this method in ONE 4 

Retro 12 Gosh this one was hard ! For a long time I had all pieces to solve this level, but could not set them up properly due to timing : mine too soon and everyone will splat, or bash too soon and you cannot mine later.
The idea to mine seemingly for nothing is just brilliant : mine for nothing but save a brdige, then use the bridge later to make the mine useful. Wow 

Avant-Garde 1 Back to lower difficulty with the start of this new rank, nothing much to say here. Great and doable level for newcomers, Armani can create them too !

Avant-Garde 2 I had fun toying around with the new skills in this weird design, makes me wonder what namida's room actually looks like 

Avant-Garde 3 Still in the doable difficulty, walkers are that strong.

Avant-Garde 4 Nice level where some lemmings have to take one route, and the others another route. Thanks again for the marks on the ground to place the laserers !

Avant-Garde 5 It starts to get tricky here : one miner for 2 tasks.

Avant-Garde 6 Extension, extension, extension. Good level, you'll definitely struggle without extensions.

Avant-Garde 7 Very good level, and taught me the wall-to-wall slider/jumper (Super Mario can do it with no particular skill in recent entries in the series !). Thank you for this because it will be used often later !

Avant-Garde 8 Zombies have to be led here, but dont touch them ! Walker is strong, did I say that already ? Also you have to manage builders correctly here : I kept on trying to make the water pits crossable in both ways, but it just wastes builders.

Avant-Garde 9 The Sled was a really difficult level to me, mainly because it looks like I'm not that good with gliders.
I spent a lot of time deciding how to escape the worker at the beginning, there are so many possibilities. But figuring how to extend the fencer was even harder. I used the stackers incorrectly and had to extend the fencer with 2 stackers only, which seems impossible here.
In the end I got a quite elegant solution, if I say so, where a single lemming can build the 3 necessary stacks by himself, thanks to a well placed stoner. I think this may be a bit backrouty because I have no use for the 3rd climber, and save one more than required ?

Avant-Garde 10 Now Armani shows his evil face : lead me to think I need the 3 provided stoners to fill that bottom gap 
But if you use all 3 here, then the level just does not work. Then count the pixel and use air-lem to make the work with only 2 stoners : brilliant idea !
It is worth noting that if you remove the first little gap to be filled and provide only 2 stoners, then the level will be easier bc player will have no choice but to fill the bottom gap with 2 stoners. I'm sure Armani thought about it and put that other gap as a bait. He's evil I told you.

Avant-Garde 11 Great zombie and jump/bounce everywhere level !
There are many ways to get up there within the (non existent ?!?) time-limit, but only one will work with the rest of the level.
Here I was stuck for a day or trying to figure how to free the crowd after getting rid of the zombie and forged the path to exit ; I always had a stacker left that I did not know where to use.
My error was a beginner one : think that a single worker has to do everything. Here, once the crazy bouncer has done his job, he can just exit peacefully and leave another worker from the crowd do the rest of the job. Nice touch.

Avant-Garde 12 Huuum, this level made me change my mind.
My mind before :
1) "pickups are not that great, their location and content give away too much of the solution of the level"
2) "unneeded pickups are just plain boring and bad design to try to fool the player"
My mind after Avant-Garde 12 Presents For You
1) "pickups may be fun and allow to create nice puzzle"
2) "unneeded pickups are necessary for point 1) to be true".
Here we have a great exemple where the unneeded pickups make the whole level good.
Solving the level was all about finding the most obvious and straightforward route for the worker up there to free the crowd, and make everything possible to try to stick to it, no matter which red-herrings pickups you leave behind. If you can do this successfully (and this involves using a cloner at the most improbable place of all), then the level is cleared in no time.
On the opposite, if you start thinking in terms of pickups first, try to get them all, or even focus a bit too much on them, then you wont be able to clear.
So yeah, if you remove the unneeded pickup, the level becomes too easy. It is also splendid that those unneeded pickups do not create unwanted solutions, but for that you can trust Armani and his secret weapon : give basher pickups in a level that does not need more bashers.

Avant-Garde 13 Thank you for the knid words. I remember 2021 to be a weird and rather bad year, as 2020 was before. But hey, now we're over it, have more kids (congrats on your again !) and life continues. So you were right.

Alpha 2 : first clear I went for killing all Zombies with the trap up there. It was satisfying to watch them get squished
Talisman took much more time, hard to imagine a way to trap the zombies and escape at the same time !

Alpha 4 : I could do the clean compression required fo the talisman without using the RR. I guess with the given miners and how you can adjust them, you can just create a compression pit which has the correct width for them to compress cleanly. The walker and empty bashers skills allowed to perfect the compression and loose only 1 lemming to the trap.

Alpha 5 : how hard is this one ! Normal clear is manageable, but talisman requires to not loose a single lemming and this is another story.
In the end I used the "take it as it comes" approach. Meaning I did not make many plans ahead, but just used "optimal" methods when they were needed to progress through the level.
Twice I used the platform bricks that go through terrain when the platformer gets stopped by a very thin wall. This reminded of some Armani's levels which used that too, crazy.
In the end I did not have that much trouble getting a close enough crowd to trap them with the last platformer.
This level certainly taught me a lot about sliders, jumpers, platformers. Thank you !

Alpha 6 : what a nice level ! It took me some time to understand what needed to be done, and much more time to do it in under 1m30s for the talisman. "Quick Sort" is definitely the correct name for this talisman ; can you imagine a "Bubble Sort" level tan x dx ?
As everyone, the hardest part was to sort out the floaters from the swimmers. I did it using very close compression, plus the very small delay given to floaters when they open their umbrella.
In the end I think I have a somehow clean talisman solution. Then I looked at Ichotolot's solution to compare and say proudly (no pun intended Icho  ) : your solution is a total mess ! Mine is cleaner 

Alpha 8 : I love this level ! I also learned a lot about laserers here, and could do a save all.

Alpha 9 : kind of easier than the previous level to me, same mechanics used.

Alpha 10 : now this is a masterpiece ! First clear I killed the leftmost zombies, and avoided the right ones. It looked natural but used a lot of resources.
Second clear for the talisman gave a real awe moment :  realization that I could extend that basher all the way through to free both the right and left crowd !
But then putting that extension in place was really tough because so many things have to be taken into account : platform all the way through at the correct height, leave a zombie alive somewhere so that the basher turns into one and does not enter the exit, make sure you have enough resources to free all 3 crowds at the end.
My solution works, and use all resources.
Then I watched Icho's solution for the talisman, it is mainly the same one but is more insane with the basher going down some bridges, and the flow of builders in a hurry at the end to build the necessary bridges. Crazy !
Congratulations for this brilliant level.

Espilon 2 The problem is quite clear after some tries : if you build from the platform then the lems splat before the exir. If you build from the floor lower, the splatform is not high enough. So what to do ??
I love this solution

Espilon 3 I found this one very hard, mainly the part when one needs to avoid the splat by tweaking the diggers. Maybe there is an easier solution.

Espilon 5 Yes, the worker can do everything. I'd think this solution is backrtoute, since it is a very straightforward level this way.

Espilon 6 An occurence of "trigger the thing that will unblock the blockers, before the blockers are even set". Nicely done.

Espilon 7 Roadblock for some days to me. Dolly Dimple bridge on the left side is ok. But the blocker freed by the bomber on this thin floor of the bridges eluded me for a long time. Hard to execute !

Espilon 8 Favorite of kaywhyn, and hard talisman. Discussion above.

Espilon 9 The solution appears quite quick here, but the timer is the issue.
And now appears a very rare case : timed level where if you free the crowd too early, you'll actually loose to time ! Great design !

Espilon 10 Very good finisher for the rank. I love how it is called "what have we learned so far ?" and indeed uses many techniques already seen : Dolly Dimple bridge, mid-air bomber. Plus a blocker used as a waiter, I love them. Brilliant level.

Delta 1 The first level I actually played from the pack, due to my weird habit of playing the ranks backward. And that was a tough start ! I finally got that needed half-turn by having 2 very close lemmings : when one of them becomes a stoner mid-air, the second one gets trapped in the stone and turns. Wow !

Delta 4 Another case of basher extension with platformer. Same method that I used in Alpha 10, but way easier to set up here than in Alpha.

Delta 6 Intimidating at first due to the lack of constructive. Thoug as Icho said, once you see how to do it, it is not that hard to execute. Taught me a lot about stackers too, nice.

Delta 9 Tough one. If like me you want to keep a builder to get above the trap and be able to get over the last gap with an isolated worker, you'll have a very hard time !
Just bomb the trap, and accept to build the last gap while some lems are drowning looks easier.
For some tries I ended up a lemming short of requirement, then I had to willingly cut the shrugger animations in some builder to save some frames and reach the required number.

Delta 10 Not my favorite level I must say. This is the kind of level in which you have to experiement to see what does work and what does not. No real puzzle involved, just trial and error.
After many tries I thought I was about to give up, when I finally could go up that last step with a mid-air stoner triggered right before a builder. This allowed to go higher than the builder itself, and that was done ! I was relieved.

Taxing 3 I, Me, Mine, Miner : One of my favorites. I'm usually not that good with miners, and this level taught me again how  to use them as delays, really nice.

Taxing 4 Symmetrical Structure System : Backroute I think ? I save 79/76 and spare many skill : just build a giant splaform by escaping a athlete, and free the crowd by a nice bomber.

Taxing 9 Slow Esthetics : This was hard to me ! Using the floaters at different places to allow builders to set up 2 bricks instead of one before the next lemming come was the key. Frame precise but fair I'd say.

Taxing 10 Pillar Confusion : those pillars are indeed confusing, great design ! Backroute again I think as I save 24/22 and have leftover skills. A single worker was enough, the long digger at the beginning helped a lot.

Taxing 14 Bubble Trouble : Mean time limit ! I had to use not less than 5 workers at the same time, so this level must please kaywhyn ! I end up with many skills left again and save 20/15 at the very last second, so this may be unintended.

Mayhem 8 The Law of the Jungle : I save 79/76 by going straight to the exit. The crowd is freed by using the pixels removed above a miner's head when it starts.

Mayhem 12 Shorty Deep Inside : I spare a miner and a floater in this very limited skillset. This is possible by catching all those not-so-close climbers with a builder, but it is frame precise and needs many tweaking on all required lemmings.

Mayhem 14 Lemmings Fever : I love this 1 minute level ! There are so many solution without the timer, but I guess only the most efficient of them work in under a minute. I loved the use of the bomber.

Mayhem 15 It's All About The Style : Excellent level ! The use of the diggers to free the blockers at the end is very ingenious, took me a long time to find.

Mayhem 16 The Scaffold : Is that a backroute ? I save so many skills that I think it is. Hardest part was to figure out the left blocker.

Mayhem 18 The Enigma : the miner extension was a must to spot. My way of sneaking under the OWW in the middle looks unintended. It saves some skill and does not use the rightmost part of the level at all.

Mayhem 20 Kreuzung At The Mountain : I love this marathon level, mainly gotta get the left lemmings to the right exit, and conversely, with nearly unlimited builders. I played it several times to try to optimize and could save 99/95. Could not make 100% save though but I'd say it is doable.

Mayhem 21 Enter At Your Own Risk : I agree with Icho and others here : this level is great. Nuke solution did not occur to me that fast because the save requirement of 72/80 is pretty high. So one has to optimize correctly to reach it, but execution is not hard actually once you know how.
This reminds of a certain One 5 level in the Save One pack, though I certainly created it before playing this Mayhem 20.

One extra Lem saved, certainly by sparing a bridge over what's intended to stop the miner before it falls to the bottom.
To achieve this you have to place the bomber, miner, and 2 builders in pixel-perfect places. See solution if interested.