Mesmerizing
Intended!

Mirror World
There's a minor difference between my solution and yours, but yours is perfectly acceptable too.

In the Rear with the Gear
Intended!

Down the Rabbit Hole
This one I may call a backroute.

Terrarium
Acceptable solution! I'll attach my talisman solution below!

The Chosen One
Perfect solution! Yeah, the skillset is a bit unusual. When I made the level, I first chose several skills and limited myself to using only those, and then tried to find interesting interactions between skill types that don't normally interact much.

Mirror World
I'd consider both your solution and Dexter's acceptable.   The main idea I had in mind for this level was figuring out how to make a splatform with two builders so that the crowds from both sides can land safely. I'll attach my solution below.

The trigger areas of exits(and most other objects) have fixed relative positions. Because of that, rotating/flipping/inverting them can sometimes make the trigger areas look visually odd. That's why people usually avoid things like inverted traps or water except for aesthetic purposes, at least not in ways where the unusual trigger areas affect the solution.

That said, if someone asked me "Should a shimmiering lemming be able to use an exit attached to the ceiling he's shimmiering along?" my answer would be yes becuase it looks so natural! And in the same way, a shimmiering lemming can press a button attached to the ceiling.

The Chosen One
Good luck with this level! Let me know if you'd like a hint.

I could clear it with what looks like a backroute since I spare the shimmier skill. Then I looked at Dexter's solution who also states he has a backroute. His is quite similar to mine, except I use heavier timing things to make the left bunch of Lemmings turn around in time before splatting from the digger pit on the right side. Joining my solution if anyone is interested.

Looking at Dexter's solution I also noticed that he makes a pionner use the reversed exit with a shimmier skill, good job!
This never occured to me because the Clear Physics Mode shows me that the exit trigger is actually floating in the air, so seemingly not reachable from where Dexter reaches it. I'm joining a CPM screenshot where you can see the exit trigger floating in the air, and Dexter's lemming exiting while not going over this trigger.
So questions : is this a bug in the display ? Do all of you see the exit trigger floating in the air or is it just me ?

01_The_Bad_Beginning
It's an auto-level, just like the original first level of Pimolem. The path the lemmings take forming the letters 'L', 'E', 'M' is a nice little touch!

04_Emerald_Cave
Something tells me the intended solution involves sending one climber over the exit area to build the bridge from the other side. That way, you can solve the level with 10 skills, which perfectly meets the talisman condition. And it's much more interesting than just building non-stop!

09_The_Strange_Relics_of_Lemnos
Simple skill set, yet the level has a very clever solution.

11_Minimal_Design
Possibly the hardest talisman in the Calm rank

12_Ancient_Crash_Site
It's very clear where to use all three bashers, and having only one miner to deal with multiple gem obstacles narrows down the solution. It took me several attempts to perfectly execute the builder-miner combo.

14_Pagoda_St
A great level where you have to be creative with diggers and miners to compensate for the lack of bashers. I think I might have bypassed the second half of the level by building over the second pagoda structure though!

15_Standard_Test_Chamber
This level reminds me of playing Portal for the first time.   The companion cubes, the buttons, the guide lines showing which object is connected to which button. It's all there!(well except for the portals themselves )

19_Iron_Industry
Probably my favorite level of this batch. I love the logic behind it, figuring out the sequence for collecting pick-up skills and how many lemmings to dispatch for them. Not to mention, the level layout looks fantastic.

https://youtu.be/lhHfWl9ZTnI?si=4iDggUQzGkV9T7jR