Unconventional Techniques - A perfect solution. One of the things I tried to accomplish with these levels, was a subversion of the usual level solution trope of 'Contain the crowd, send out a worker lemming, release the crowd'. Several of these levels manage to do this by having the lemmings all move as a group to another area before the level is properly finished.
What lems beneath - Another nice solution. This level was intended to use the trick in Epsilon 10, where a blocker is freed by a falling lemming turned bomber. Your solution is fine though.
A different kind of problem - Perfect solution! What I find amusing about this level is that you can generally allow lemmings to walk around without having to worry about them. They'll all reach an exit eventually!
Do I have to do everything? - A very nice solution!
Send only the finest lemmings! - Perfect solution!
Precision engineered lemming - Perfect solution! You'd got the corret solution in your letsplay, but you rejected it when the lemmings splatted. I kept thinking, "Block a bit higher up so it's a lesser fall!"
Round the bend - A very nice solution.
Looking back, I should have bumped this level back towards the beginning of the rank. It is particularly easy considering its place in the rank.
Don't forget the builders... - Another great solution. One little tip that you may be interested in: when a lemming turns around inside a bomber crater, if you assign a miner on the very pixel he turns the other way, he will carve out a small vertical chunk of land. Very useful for a climber...
Tarry not! - Perfect solution! This level is a personal favourite of mine. As you pointed out, the solution can be deduced logically!
What have we learned so far? - Perfect solution!