The time is low to match with the other US state quizzes. I do agree it is low however (especially for a non-American, I wish I could modify the time a little depending on which country you took this from haha).
The methodology is not a problem, the qualities measured by the HDI (such as per capita income, health or average education) are measurements you can measure tangibly. However, using the HDI as a basis for quality of life is still flawed. The inequality-adjusted HDI attempts to remedy this by looking at the average person, rather than an aggregate sum of a society, and this index is quite punishing towards the US as a whole for its inequality (at least compared to other developed countries).