5 - The Crystalline Fortress Ok yea, nothing that I'm not familiar with, since I know the stuck climber glitch all too well. The difficulty is simply getting a Lemming stuck so that he can slowly climb and ascend through the terrain. It apparently doesn't work if you try it on ground level and need to get it stuck in the wall along with a step/staircase of some kind. However, it does work, as I have learned from another level in this pack that it requires the blocker to be removed in order for the stuck climber glitch to actually work. I've managed to save plenty of skills here, but I'm sure this is still an acceptable solution Also, interesting that the RR is 0.

6 - Now you're stuck ( part 2 ) - One that I was indeed stuck on until an idea came to my mind: Isn't it just get multiple Lemmings stuck in the wall? I tried that and sure enough that was the answer! One annoying thing is when trying to get Lemmings facing to the left getting stuck in the wall. Several times I would put a blocker close enough to the steel block but the Lemmings that are close to it would just go past the blocker. Hence why I had to make some Lemmings build and then quickly set a nearby Lemming to block in order to achieve getting them stuck. Two solutions, the second of which is a much nicer way to do the level since it allows you to save way more builders this way instead of like the first one where I had to frantically assign builders as they came to the gap.

7 - The squares fight back (part 2) Admittedly, I was spoiled here, but that's only because shortly after I had completed the original level by Clam Spammer I watched your video to compare, and in that video you show two solutions to Clam's level. Even if I wasn't accidentally spoiled here, I'm sure I would had eventually figured out that you're supposed to get a stuck climber to slowly ascend high enough in order to leave a builder step to make the fall survivable, given that you cannot use the glitch where climbers fall a pixel away from the wall at the very end due to the gap not being wide enough. Definitely a very long and tedious level for my liking, even with the time skips. That's why you see me just brute forcing my way through the top rather than build more lengthy bridges at the bottom

8 - Spaces within spaces As mentioned on Discord, I thought it highly unlikely I would get the level solved even though I know the stuck climber and giant leap glitches are required. Indeed, I had tried the compression method here before, I guess I wasted at least 1 or 2 builders before and hence didn't have enough to later do the glitches. This is another one where I did see your challenge solution to completing Taxing 4 in a minute, but it doesn't matter, since it should be really obvious that the giant leap and stuck climber glitches are the only way to get them home on this level due to the indestructible steel block covering up the exit completely. So, I guess I really did beat the odds here and got the level solved after all!

Also, I forgot to point out that the wheel traps don't kill the Lemmings on ground level. They probably do work if you build near them. I haven't checked the ones that are upside-down, only the upright up ones.

9 - Science from the 4th dimension Backroute as you have told me on Discord. It's definitely one of the hardest levels of the pack. Indeed, the top entrance is the hardest to figure out, but this is another case of an idea came to me all of a sudden, where I thought, wait, blockers have the ability to disable traps! Thus far, they have commonly been used to cancel steel areas, so your level is pretty unique in this regard of requiring one to disable the steam blower trap. It took me a while to come up with this idea even though I had previously seen this in the final level of geoo's pack that requires disabling the L1 Fire fire coalboxes with blockers. Nice level and I can't believe I failed to realize how very close the left side of the level is to the left edge boundary! I was actually wondering if climbers will climb up the boundary like they do on Lemmini, but I guess they don't on Dos. Good to know, this is something new I learned despite having grown up with the Dos version of Lemmings! 

You should start by sending one worker to the left (give him a climber and a floater + use a blocker to contain the crowd). The worker's first task is to dig down. Where to dig is the main part of the puzzle and once you figure that out the rest of the solution will fall into place naturally.

First, the two workers must meet on the lower floor and build a bridge together. After that, one of them should go back upstairs to complete his own task.

Near the starting area, there's a pit with a basher pick-up. You need that basher, but you can't let the crowd fall in and get stuck, meaning you must send only one worker to collect it, and then save him with a climber. You also need to collect one floater. There are two floater pick-ups in the level, but one is a red herring. The one in the top-right is the red herring.

making the catwalk shorter

This one actually has two intended ways, since the basher and miner are interchangeable!

I was going to dig away the left pillar to show off, but it's actually pretty dangerous because the lemmings follow the climber, and it risks causing them to splat as they fall down the digger shaft that's tunnelled to set up the miner.

You can dig the left pillar on the far left side with the climber instead of the right pillar. That works too. I thought about blocking this alternative off but I decided to leave it in as another nice way of solving the level