I played this pack several months ago, but I unfortunately didn't have any replays, so I went back and rectified that last night and finished off the rest of the pack earlier today. So, here is my complete set of replays for Copycat Lemmings. This is for NL v1.43, and AFAIK this pack cannot be converted to New Formats for technical reasons, mostly owing to how this started off as a Cheapo pack. So, these replays probably won't be of interest to anyone but Essman, but once again I'm simply attaching my replay set just for the sake of completeness and sticking to how I plan to eventually post my replays for all level packs I play here on the forums, in addition to possibly any LPs or video solutions I upload to my Youtube. Also, I believe the fall distance before splatting is much larger than it usually is in NL? Probably that's the way it is in Cheapo, but I don't know for sure since I have never played or tried Cheapo.
Regarding my experience, besides bsmith's level pack, this is the very first time in months that I have played very old formats NL. The absence of skill shadows took me by complete surprise and so made some of the levels a bit annoying, but at the same time it's at least identical to playing the game on the other platforms/engines, since they don't have it either, so I didn't mind. Fortunately, if one wants this experience of playing without skill shadows, the v12.10 NL now has an option to disable them. Not sure if I'll disable them, though, since I'm very used to them now. The most annoying is how there's no hotkey setting to go to the last skill assignment, and so I had to make do with the 1 and 5 second rewind hotkeys.
Regarding the pack, this is a very well-done pack. Despite the clunkiness of the v1.43 NL player, I enjoyed and liked almost every level in the pack. It's very similar to Geofflems but is much easier IMO. In particular, I absolutely loved the wide variety of levels in the pack, and the solutions of the Fun levels here are interesting and not dull like many of the Fun levels of the original Lemmings. Fun 27 - I know it's around here somewhere comes to mind. As the title suggests, it's a find the hidden exit type of level, but it's very easy and there are indications on where to look. This is a level where the title gets cut off, and I think there are several others, but this is just a drawback of the v1.43 NL player. No real challenge until you get late into the Taxing and Mayhem ranks.
This time around, the pack was a much faster solve for me than I remembered despite not having any replays due to not having the setting to automatically save successful replays at the time I first played the pack months ago. Even for my second playthrough of the pack, I still agree that the hardest level of the pack is Mayhem 25 - Opposable Lemming, although this time I had a much easier time with it, probably because I pretty much still remember the solution from when I first played the level. It's still a difficult level due to the builder checks in this NL version, though.
I don't get the point of Taxing 5 - More armatage shanks, the repeat of Tricky 16 - Armatage shanks, since the solutions are exactly the same.