Level 1 "Rush Hours": a very difficult level to start off with. Needs knowledge of several tricks, some familiar to most NeoLemmix players, others less well known. I wasted some time with complicated manoeuvres at the bottom left before realising there was a simpler approach, and realising the importance of the web. I did not even think of trying for the talisman – managed to save the required 63 but needed 1 more minute and 3 more Miners than the limits set for the talisman.
Level 2 "Go Around Inferno": a much easier level. It's obvious where the Cloner has to be used. The challenge is to get through the obstacles using only 2 Bombers – this needed experimentation with the release rate and careful use of Climber.
Level 3 "Don't Let Walls Stop You": this needed a lot of thought and to work out how to save a Bomber, as it looks like you really need 3 or 4 but have only 2. In the end I turned to Master88's Miner-Cloner-Bomber trick – see https://www.lemmingsforums.net/index.php?topic=6303.75 post #77.
Level 4 "Climbers Escape shaft": another relatively easy level, even to unlock the talisman. The main challenge is to ensure that the brick to seal a gap is laid after the entire crowd have climbed past it but before they fall back down.
Level 5 "Offer a Helping Hand": it did not take too long to figure out the main elements of the required strategy. But it's the difficulty of execution that puts the level in this rank. The only way to access the exit is by using Builder plus Blocker, which obviously needs good synchronisation; but the two lemmings involved also have to be well synchronised for an earlier trick, and this leaves little opportunity for slightly advancing or delaying one of them between the two synchronisations. The clever design of this level means you have to think carefully about: how to route the 1st lemming so the 2nd can loop until its partner is ready to join it; how to set up the 2nd & 3rd lemmings so you can fine-tune their release to within 1 or 2 frames; and how to get some flexibility in the timing and location of the first synchronisation so you can adjust the timing of the Blocker's arrival relative to that of the Builder.
Level 6 "Agoraphobia": not yet solved. As far as I can see, both Platformers – as well as both Builders and a Stacker – are needed to rescue the crowd from splatting. This means that no Platformer is available to get over the traps, so the advance lemmings need an alternative route – which I have not yet found.
Level 7 "Strained Atmoshphere": an attractive puzzle. Some elements of the solution are clear immediately, but it took me a while to see where to deploy the Cloner and Shimmiers. In the end I was able to save 1 more than the requirement.   
Level 8 "Lemmings Are Grounded": not yet solved. I have not spent a lot of time on this, but at first sight it looks like more of each skill are needed. I am assuming that the solution involves an advance lemming going along the top, mining to the right and then being turned by a Blocker.
Level 9 "All Stepping Stones Don't Help": not yet solved. The title says it all. Besides the usual challenges, there are 2 problems I can't see a solution to. First, the top right 'stepping stone' has to be removed so lemmings can slide down the wall, but the Digger cannot slide, it just splats, even if I dig after reversing. Second, how to avoid the 3 non-climbers getting trapped in the trough to the left of the exit – the only solution I can see involves sacrificing 1 lemming, but all have to be saved.
Level 10 "Sky Bridge": I particularly enjoyed this puzzle. The biggest challenge is to combine compressing the group with reversing an advance lemming so it can build a bridge for fallers. After initially falling 1 short, I managed to save 1 more than the requirement.