The first question will be in the medium bin difficulty and it gets harder as you get each one right succinctly. It eventually plateaus off and perhaps even gets easier as you are halft way through within the test or towards the end. Hence, someone who gets more questions right in the beginning, say first 10 questions, but who gets the same number of questions right in the end will certainly get a better score than someone who missed the early questions and got most of the later ones right.
Of course, there will be a trade off between spending more time getting the early questions right and answering all of the questions because you are penalized for questions which you do not answer. You have to practice and build up your stamina so as not to get caught not having enough time during the test.