In reply to Fishrubb:
One thing is that the app has white text against a mountain scene background. In very good viewing conditions, I could read the text fully, but some white words over snow features, e.g. 'ascend' on the scoring screen, did not contrast sufficiently with the background. I also couldn't zoom the text.
Given that I have difficulty reading Kindle books outside in sunny conditions even though the Kindle app has higher contrast and a plain background, I'd be concerned about the readability of the text in mountain conditions.
If the user clicks on 'next' before answering a question, then they seem to score zero for that question. I'm slightly concerned that an accidental double press of the 'next' button, skipping a question, would give an erroneously low score. Could the app be changed so that the user cannot click on next until they have answered the question. Or at least there could be a warning on the last page mentioning that questions have been skipped and the real score could be as high as X.
Also, the final score screen is a single screen which asks the user to check the score down the bottom. For these kinds of tests it's usual for them to show different final screens depending on the score obtained, so that different feedback is given for different levels of risk. Particularly for higher levels of risk, Flashing red lights or another analogies may help reinforce the danger and importance of the result.
I hope I haven't been too critical here. In my professional life I often end up having to give critical analyses of student work of this sort, so I may have inappropriately been too detailed in my criticism. If so, please see username for explanation.