Oni 1 -
Cosmic Mansion Deceivingly difficult 1-of-everything level to start off the rank. Seems I made the solution harder than it needed to be, as I saw Armani's solution and that one is definitely easier to do. Other than the digger at the start, the rest of the level isn't easy. As usual another great one from Nessy.
Oni 2 -
Attic Antics Another somewhat huge level that looks challenging but it wasn't too bad. The hardest part to figure out was how to dig away the second OWW before the others arrive, but this is where I used timing to get a second worker to come at a time so she doesn't splat while the first digger is going. Great level!
Already played Oni 3 from LOTY2020. I used the same save all solution here as I did there. Same with Oni 7, though I think my solution is slightly different this time. I don't think I had a basher left like here. I agree it's definitely one of the hardest of the pack!
Oni 4 -
Chaotic Neutral This one should be another very bad backroute

I really like the preassigned neutral disarmer shimmier

Oni 5 -
Park Souls One of the hardest of the rank. The start is hard, and also figuring out how to get on the other side of the OWW. I don't know if I made the solution harder than it needed to be. I really like the mining down to the steel where the anti-splat pad is on the far bottom left.
Oni 6 -
Resident Treevil Another hard one, but it really seems I overcomplicated this one, especially at the very start. It wasn't easy to figure out how to get the crowds down safely and to eliminate the zombies. Armani's solution is far better than mine. His solution is starting to make me think the intention is to go through the bottom rather than everyone goes over the top, though I think I can see the latter still working, especially if you have some jumpers to do so so that a builder isn't needed.
Oni 8 -
A Christmas Carol Tea Yet another that's quite possibly the hardest of the pack. The only level in the pack where I needed more than one video to solve. I didn't realize a miner could do the job in the structure at the bottom near the exit so that you don't need to use a fencer. This one seems to require very good precision with the basher cancelling midstroke, though I wonder if I could had simply used jumpers to get two climbers up the left side of the structure while the basher is going. Before I was successful, I kept running out of the essential skills Then I watched Armani's solution and that's exactly what I was trying to do, but turns out it's possible to just use a miner and not need a digger to do so too. I was also dumb and forgot that you can mine from the left side at the top

Awesome level nevertheless that managed to give me so much trouble

Just like Armani said, I too found bad backroutes to Oni 9 -
Sheet Happens and Oni 10 -
Out Past Curfew 
Oni 11 -
Find another streetcorner for your noise Looks intimidating and hard due to the tall size, but it wasn't too bad. It's not easy to figure out how to get to the neutrals to rescue them. I liked this one to an extent, though I think I overcomplicated the part with the basher in the middle, as it required careful placement to not also chip off the platformer bridge. I think if I had the walker skill available it would had not been as precise.
Oni 12 -
Friends of Varying Talents Wow, I really like this one!

Getting different specialists to do different parts of the level to get everyone home safely. The only one I didn't use was the floater, but I used the other 4. A lot of the solution can be deduced based on the design and which specialist is most suited to the task.
Oni 13 -
Mire of Magenta The solution here is very cool and all, but it's quite unfortunate that this comes not too long after playing a few levels that require a lot of precisoin

Most notably, the original Rigel 10 from Mike's Lemmings Version 2 and Hard 1 of Unusual Lemmings. Even with the visual indicators in the terrain telling where to place the builders and blocker, I still had to tweak the skill assignments so many times, and eventually after a while it gets very annoying. Needless to say, levels where the solution is obvious but still requires a lot of tweaking until everything works is not fun IMO. I don't think I'm the only one who has this view. The builder/miner combo I tend to like, but when you need to use several builders in different directions to do so, then you're just asking for way too much precision, and that is what makes the level less fun as a result. Of course, I'm a hypocrite saying this as I seem to be a fan of very fiddly solutions when solving, but when I'm designing I try to eliminate it as much as I can from my own testing.
Oni 14 -
Vulkovan Park Another level that requires some precision but not as much as the previous one. However, in this case I really self-inflicted a lot of precision and made it harder than it needs to be. I checked Armani's solution after solving and his is easier to do. Also with how I used a platformer to keep everyone safe at the start. Great level though, as I especially like extending that basher as much as possible.
Oni 15 -
The Cortex of Shang Tu Another hard one, though it's not easy to figure out how to get everyone to the exit. I'm not sure if it's possible to go up the middle to reach it. Still one of the great levels near the end of the pack.
Oni 16 -
Relieving the Stress The only thing that makes me think this is a backroute is how very easy it is to save the splat hatch at the start with a glider and cloner. However, it doesn't seem possible to go about the level any other way, so maybe it is intended to be easy to do so. I still didn't find this one easy by any means. Had the glider not go out back to the right, I think I would had struggled longer here. Still a great level, whether my solution is acceptable or not
Oni 17 -
Launch Party Another really challenging level, even more so than Geku 12, but it seems that it's still open-ended regardless. Some of my early attempts I think had me running out of the necessary skills, but eventually with some tweaking I managed to get it to work. The only thing that sucked was having to redo most of the level as I forgot the switch at the top at the start

Fine level!
Oni 18 -
Battle in the Stars! Unique in the sense this is the only collab level between Nessy and Gigalem in the entire pack. For the final level, while it's not the hardest, it's not easy by any means. It seems intimidating more than anything due to the tall size and how there's a lot to juggle and the many switches to get to. Even then, it seems open-ended as well. I'm not sure if being able to bash all the neutrals free from below is intended though. A great level to finish off the pack!