I found it decently challenging actually. I had to think a bit in regards to how to reduce the number of skills I used in order to merge to the two crowds of Lemmings as well as find a way to get the Basher pick-up without turning the Lemming around...
...and the fact that there are Blockers and you can lose a Lemming disguises the fact that you have to sacrifice one to the Ghostbuster trap so the pathfinder can get through. Building through a thin wall to provide a platform to land on is quite an advanced trick as well.
It's certainly easier than some of the other levels, but you don't have to make them hard. They have to be enjoyable, first and foremost, and this one was very enjoyable - well done. The up arrows look a bit weird, but I gather these are for patching a backroute and hence they can't be left-facing like the rest (or steel, since the rules forbid it).
Any luck on solving my levels? And opinions too.
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Oh, one extra artistic complaint... the up and down arrows on the Fire tileset really need to scroll in the same direction as the arrowhead, because it's very hard to work out exactly how much terrain is covered by them, even with clear physics enabled.