For a moment, I got really scared that you were going to backroute the level when you sent up the clone up the left side, as that was the part that I was trying so hard to stop Armani from using, but alas I failed spectacularly there for 10 versions!
However, you both thought the hardest part was cloning the builder 3 times to make a wall, i.e, a blocker substitute. When you were trying to figure out how to save a blocker, at some point I screamed, "You know what's needed Icho, you just haven't realized it yet. You enforced this trick in one of your United levels!" Also, I found it interesting that you learned the release of a blocker with a nearby bomber trick from an LP2 level. I don't recall any level from the pack that requires it, though
Both you and Armani also thought the bottom left opening was a design error. It is not, actually! Think "The Glacier Station" from your Reunion pack! Many people thought it was for decoration, when in fact it's necessary for the solution. It's the exact same thing here. It's completely intentional to stop the cloned miner
Here, I could had avoided all the version updates by putting either pickups or a button in the little cave, but I didn't want to make it super obvious that you need to do so. Therefore, I left in the red herring of going up the left side so that if the player does attempt to take it, you're not going to have enough to solve the level. Or, you'll lose too many lemmings as a result.
I also hated to make the bombers and blockers pickups, as I felt the solution was way more obvious as a result, but Armani has told me otherwise. He has said the level is still very hard despite the pickups, so looks like I've been proven wrong about the solution being more obvious.