Master System has 120 just like Amiga / DOS; most are the same but some are completely different levels, and some others have differences.

Genesis has 180. Some are the same as Amiga; many are unique. A small number of the unique ones are OhNo levels remade in Orig tilesets, but most are completely unique to this version. Many of them are also regarded as among the best official levels.

SNES has 125. 119 same as Amiga, 5 taken from Genesis, and one unique.

Win95 Lemmings (only counting Orig and ignoring OhNo) has a few less than Amiga. The special graphics levels, as well as Fun 13 and Tricky 21 are removed (without any replacement). There might have been others, not sure.

The current logos were created around 2014 when we moved from lemmingsforums.com to lemmingsforums.net. They were created by a user Prob Lem who is no longer active, if I remember correctly. She likely created them using rips of the logos from the games as a guideline, but I didn't ask about the process.

Uploaded V0.0.27.0. Nothing huge here, but I've had these fixes ready for a while and figure better to release them than just have them sitting around in the codebase.

Changes:
> More slight improvements to rendering issues.
> Fixed a minor bug with loading L3D level files that use the Fun 8 effect.
> Fixed an issue with mouse-based camera movement when the cursor is confined to the game window.

Game: https://www.neolemmix.com/download.php?id=580
Music: https://www.neolemmix.com/download.php?id=530
Replays: https://www.neolemmix.com/replay/L3D_Loap_Replays.zip (unchanged from previous version)

I have moved this to the main NL board as it is not a bug or suggestion. In terms of your actual question, Icho summed it up pretty well.

I do recommend installing to a clean folder if upgrading from one major version to another (eg. 12.11.X to 12.12.X). You can still copy levels and progress from your old install. When upgrading between minor versions (eg. 12.12.4 to 12.12.5), you can install over the existing copy, and I generally provide upgrade ZIPs that contain only the files that have changed.

If you are upgrading from a really old version (10.X.X or 1.X), you should set up a completely fresh install as most files are not compatible between those and 12.X.X.

Perhaps losing a challenge should have a penalty of some kind? Or, alternatively, a cost that must be paid to even attempt to challenge.

It should already be limited, but I'll look into it.

They show how many more lemmings you needed to reach the save requirement. For example, if the level requires you to save 5 lemmings, and you saved 3, you'll see 2 black lemmings. If you saved 5 or more, you won't see any.