"Steps and Pixels" - The diagonal pixel thing only occurs in one place, and I think it could be easily overlooked,
and is even possible to avert altogether EDIT: no, it isn't, I wasn't quite thinking straight when I wrote that. I think more emphasis on that is needed - maybe some downwards steps with it near the end? That aside, this level is pretty good - and the skill queueing feature makes it a lot more suitable for new players than it would have been previously!
"Stepblocked" - To me, it wasn't immediately obvious that I wouldn't need the Walker later, and thus I used a trick that might not be expected (RR99 right away, last lemming builds instead of first) to avert the need for it near the start. Even if the player realises the walker is unneeded, should they choose to assign the builder first, the 3rd lemming gets in the way of the most obvious spot to assign the builder, making the shadow hard to see. I wonder - could the release rate be a bit lower here?
"Concentrated Force" - The save requirement as it stands requires timing the crowd release so the crowd merges with the basher. I don't feel this adds any value to the level as a tutorial, so I suggest dropping the save requirement to 43.
"Blocked In Your Favor" - Very nice level!
"Combine & Conquer" - Saying "a well placed builder can keep a Fencer going" is misleading. A fencer will
always continue up a builder bridge. No issues with the level itself IMO, although I think demonstrating the fencer case too would be easy enough.
"Equal Distribution" - This one has me stumped. Which would be great in a normal pack, but a bit worrying in a tutorial pack.
"Special Staircase" - The builder not only doesn't need to be interrupted, but
cannot be interrupted. Instead, he should be allowed to hit his head. Is this intentional?
"Stepping Up To The Stars" - I had a walker left over - the 2nd basher didn't need to be stopped. (Perhaps you intended a fencer or miner to be used right at the top? I used the miner near the start, then fencer, basher, stacker, fencer, basher, platformer.)