QuoteI've now went ahead and recorded videos of your intended solutions to the three levels.Thanks kaywhyn!
Spoiler
About The pillars of success, you notice:
Moreover, at first glance, we don't know which path to take to reach the exit while activating the three buttons.
QuoteI would go further and say it's quite deceptively difficult despite the very minimal skillset. (...) That cancelling the digger with a miner can be really hard to pull off and even might be one that some aren't aware of, so that alone already increases the difficulty a lot!Yes, you had to find a way to do a U-turn. And I haven't seen this trick often in other levels/packs. So, I agree, it can be considered not obvious.
Moreover, at first glance, we don't know which path to take to reach the exit while activating the three buttons.QuoteIt's very easy to fall into this trap as a designer of underestimating/overestimating the difficulty of one's levels.You're absolutely right. It's very difficult to judge the difficulty of your levels yourself. Like you, I often tend to underestimate it. So, The pillars of success level is probably not easy. I mistakenly thought it was the easiest of the three and wouldn't be a problem for experienced players.
To go further, I think there was another difficulty here: these three levels are not part of a pack (where the difficulty of the levels is indicated and where they are classified by increasing difficulty), it's therefore not obvious to know in advance if there are easy or not; in short, we don't know what to expect!
Anyway, what matters is to find a solution, even if it isn't the one intended. So congratulations to you! 
You could just cancel the miner by turning it into a fencer! Your solution works well, but it's very difficult to execute.









But I almost removed it, because I don't like it very much: it requires a lot of precision.
That's why I created another level instead with a similar setting. Additionally, I put it at the end of the previous rank.
