Yes.
The job of the interviewer is to assess how well the candidate met the critieria. The criteria describe what a good answer looks like, but it can never be 100% objective, so the interviewer has to apply some judgement, which should obviously take into consideration how difficult the question is.
If the cases are "tough and unorthodox" it might be less important to you to consider angles that you've never experienced, even if those are core to the case. Often the interviewer will push you to think of these or maybe even reveal them to you.
Just like in real life, tougher problems require more work, time, and resources.
Example: perhaps you've never considered how a certain governmental body is a key stakeholder, so you miss an important part of the case. Less significant than if you miss a key fixed cost, which is something you typically can figure out on your own even if you don't know the industry well.
Hope that helps.
Allen