There, I just spent 3/4 of a post criticizing a game I really enjoyed. 
Nothing wrong with that. Criticizing a game you like doesn't mean you dislike it. I think it just means you care enough about it to openly talk about things like that in greater detail.
For me personally I don't remember Lemmings 3 that much but from what I can remember I didn't hate it. It had some interesting mechanics and ideas that I think made the game feel different while having the "Lemmings" feel to it.
Flopsy brings up a good point about the lack of tutorial levels, but here are my thoughts on that: the original Lemmings had tutorial levels in the first difficulty, which is the difficulty that new players naturally play. What I loved about them was how they didn't give you lots of text to read in order to figure out how all the skills worked, but instead they gave you an environment where you had to use one or two skills and then experiment with them a little bit. Your reward was completing a level, which would almost always give newer players the motivation to continue. Levels like the "Only Floaters Can Survive This" took this a step further. You are allowed to save only one lemming, which means that new players had the chance to see a few lemmings splat before figuring out the skill. This would then allow players to connect everything together and realize that, "Okay so lemmings cannot survive heights so I need to use this floater skill here".
Now, in a game where you are encouraged to save everyone and you have unlimited skills (the ones that aren't pickups) then this is trickier to implement. If the first level in the Classic Tribe was a tutorial level of any kind (which is possible because of its simplicity and the "safe-ish environment") you could have blocked or jumped or made everyone a walker. You can count that the player tried all this, or not. Then you have to consider that it is less likely that someone will choose the Classic Tribe as their first tribe than a first difficulty. Another problem I see with having tutorial levels is if there are easy levels to introduce things and mechanics in each tribe then you run the risk of someone learning it all in one tribe but being forced to learn everything again when they head to their second or third tribe. Perhaps this comes down to good level design? I honestly don't know how I would have handled this if I were making this game
I think making simple, but easy, levels as the first couple or few levels in a tribe would allow new players to get a handle on things but since it's still a puzzle more experienced players wouldn't get bored since they are still puzzles to figure out. kieranmiller's Lemmings 2 pack did something like this where all the skills a certain tribe was going to use was introduced in the first level, but they were still interesting puzzle levels that weren't over the top in difficulty but you still had to think about it.
On another note the unlimited skills was the thing I had mixed reviews about. I didn't mind the pickups, but honestly I would have preferred limited walkers, blockers, and jumpers. The problem with this is that now you run into a one, worker lemming heavy game (or "Worker Lemming Deluxe" as kieranmillar puts it). From a player's perspective you just use almost the same (or similar) containment process in almost every level (or maybe not. Someone can probably correct me on this
). From a level designer's perspective it basically becomes harder to create certain puzzles. In Lemmings 3 you have certain skills that are forced on you (the walkers, jumpers, and blockers). If you want to make, let's say, a containment puzzle without blockers you can't remove the blockers from the skill panel.
As for the monsters, the game didn't need them. They were just glorified traps that sometimes didn't work and I hated that female lemming-attracting monster in the Classic tribe. Traps are always dark but that... well sorry it's a touchy subject for me.
By the way kieranmiller is creating custom content for Lemmings 3 so you should definitely check it out if you love this game, and no he is not paying me to advertise it
