9 The Acid Test : first roadblock to me. There are so many was to free the right crowd that I did not know what to do at first. Finally I gathered both crowd together to make things easier for the builders. Timing on thoser builders was the hardest part, but it allows to save much needed time.

11 The Boardwalk : solution differs from Kaywhyn's. No containment needed, just some well placed diggers.

13 Cream Of the Crop : probably a important backroute. 5 destructive skills left and 9 Lemmings in more than requirement. Also the right part of the level is not used at all. Look at this poor Lem I sent over there, only to let it fall to its death when I realized he was not needed.
I'd say one is not supposed to be able to get throught the One Way pillar with 2 bombers only.

18 Kessel Mineshaft : I particularly loved this one ! Compression is easy to achieve with the many blockers given. Mining the big wall at the end is satisfying, though I may have it done not the intended way because I'm left with some miners.

20 Deux Ex Lemina : Great level for which one trick is used : the trap is actually inactive ! Is that on purpose ? In any case it helped me use the single builder elsewhere, and not the overcome the gap at the end. I save one more than required. Completely different solution than kaywhyn's

21 High Rise Lemmings : this one made me smile too. Solution is quite visible from the beginning, but I did not understand the use of the rightmost exit at first sight. Only when the blockers were freed that I thanked Scotty for putting it here 

23 Separation Anxiety : very good one ! Clean separation achieved thanks to the 3 blockers provided. Just count correctly how you split the Lemmings between the 2 groupes, or you wont save enough.

25 Down To The Wire : headache inducing level. I struggled a lot to find a correct order to dig down those wires, and to manage timing so that the gap can be covered properly. Good level for sure!
Also another example of Scotty's touch : inactive trap ! Though this one has not use in this solution anyway.

27 Open Season : hardest of the pack for me. I finally released and blocked all entrances with a single basher, all the while liberating a single worker to do the first part of the job (this release was possible with a single pixel of terrain missing, luck !?)
But then later you have to release another one for building over the bear trap. At this time I had a very dense crowd from which it took me a while to figure out how to extract a single worker again. But finally a well placed miner did the trick.
I think this level is very open ended, and ingenious. Great work !

30 Upside Down World II : nightmarish web, glad I could finally get through it. Spider responsible for it can go burn in hell.

Looking at my levels nowadays, lots of them require maybe excessive release rate tweaking, that might create unnecessary-ish artificial difficulty. When creating these levels, I thought I wanted to hide the solutions pretty well with those RR tweaks, so that no solution would be encountered by accident. But as said, release rate regulation makes the levels harder in lots of these cases, maybe harder than needed in the end.

Sparkle & Glitter I saw in a dream when I was a child and it's surprising to see how well it kind of works as a level, having few little tricks in a very minimalistic landscape. Early backroutes happened due to time limit being too lenient for unwanted approaches.

The Glade of Disbelief is built around that trick, about which Simon/IchoTolot even drew a concept art of how the builder check works.

For Mr. Dodochacalo and Mr. Pieuw is the only level I didn't try to hide the solution at all and alongside Crysilis and Zygoptera these levels that are still the only ones that aren't backrouted in any version of the pack. After all, it is a tribute level.

I didn't know that Winter Solstice is in Revenge of the Lemmings or even has a NeoLemmix version. Obviously, the miner shouldn't work on the left hatch area what it does in the NeoLemmix version now when watching kaywhyn's solution from YouTube. Also, this level has a visual quirk: the water pool on the right was designed to have 4 layers of ice on the surface, but it seems than only played in Lemmix those appear as intended (the lowest object is on the front and the highest on the background). In these other versions there's those mud layers instead of ice surfaces, it doesn't look as nice as I mentioned it to be. I guess it's possible to be fixed, though.

Feel the Pressure is the first level I ever released, it was in a Lemming level contest with a rule to design an 1-of-everything level. It revolved around the idea of merging Lemmings from two hatches in a digger pit with a RR of 87. Again, I don't think I have taken much part of the Lix/Lemmini/NeoLemmix versions of this level, but the save 47 solutions I've seen are ok for me.

Why do you all look the same? had earlier title "Why do you all look so similar?" if someone wonders if there's replays going around with that name, for example. The main trick is the main thing here, but as said, release rate fiddling makes things a bit hard.

In the Core is the only level with a clear glitch but as mentioned in my starter post of the topic it can be quite obvious to find out in the end. My solution actually involves releasing both crowds from below, I didn't even remember this before looking at my old replay. IchoTolot's solution is similar to kaywhyn's.

IchoTolot found a ridiculous backroute solution for Pedantic Lemmings in 2015 and I haven't bothered to fix it... others have found that intended solution of re-using the climber. I made the pack with all of 9 original tilesets from the games (excluding Xmas), and I chose my favourite tileset, Brick, to be the one used in two levels.

Crysilis was made in a level designing jam with a rule of making a builderless level. The title refers to the Crysilis planet level in Jazz Jackrabbit game. This is the most open-ended level in my pack and is pretty much any solution is fine type level. Yes, the right hatch area is pretty much filling compared to the two hatches area.

I can't remember exactly if Zygoptera was first a visual idea before deciding the main solution there, most probably it was. A fun fact: I wanted to use the cooler sounding name Zygoptera (damselflies) instead of Anisoptera (true dragonflies), even though the visual appearance of the level is maybe closer to Anisoptera. Also as I studied biology in the university it was nice to have something related to that in my level pack. In the solution my bomber and digger assignments are vice versa to kaywhyn's in their YouTube video and it's completely fine. Crysilis and Zygoptera are the two levels I initially meant in my original post saying "I'm a bit worried if two certain levels resemble each other too much." referring to the usage of basher mechanics.