Hardness is in the eye of the beholder, I guess, and I'm not sure that any of us (being no longer 10) are that well-placed to judge whether this was "too hard". That said, I don't personally see an issue with any question, they all seem reasonably well-posed. The "Austin" question is probably the hardest, but it also tests the skill of reading two separate pieces of information and spotting the connection between them: the bridge is in the "city of Austin", Austin is "the capital city of the state of Texas", therefore the bridge is in the state of Texas. If it's hard, it's meant to be. I don't get where the teacher thinks that you *need* to be familiar with US geography to get this, as all the information is right there, so imo it's definitely testing a skill in reading.
I think the bigger issue is that "exam technique" just isn't explained very well. How to cope with doubt, or panic? How to get in the right frame of mind? And, perhaps, better time management -- on the "eat" question, for example, it may be that you aren't sure whether "feeding" is close enough, but for only one mark it's important to recognise that it's not worth spending any more than, say, a minute deciding this. Choose feeding, come back later if you have time, move on. Here, for example, you have one hour to answer 38 questions, covering (presumably) 50 marks. Allowing for reading time, and a period at the end to check, that's one minute per mark maximum. Since you anyway need only around 30 marks to meet the expected standard, it's important too to bear this in mind. I think there's often a mentality that you have to chase every point as you come to it, rather than see the paper as a whole.
I say that with the privilege of having found exams generally an easy experience throughout my life. Which is a horrible boast, but what I mean is that exam-taking is a skill, which can be learned independently of the material. I think a lot of people practise essentially the wrong thing. Alfie did well in his practice exams, for sure, but I wonder how many of those were sat under proper exam conditions -- and in any case, to an extent the answer is "none", because the results from those mocks necessarily had no weight so it's easier to avoid stress. Granted, 11-year-olds perhaps shouldn't be expected to learn the nuance of *how* to do exams well, which brings me to my next point, namely that I think exams are a terrible way of assessing (especially young) children's performance.