It seems that the main improvement here is not anything magical about "gamification" but the idea of presenting students with progressively harder algebra problems in which they get to try out new problem solving methods gradually.
Unfortunately, this doesn't work in many classrooms because the teacher has to manage too many different students learning at different rates and can't tailor the lessons appropriately to all of them at once.
I'd think that a huge benefit "gamification" is that it allows students to learn at their own pace and without much teacher guidance. Kids figure out how to play Portal and Civilization, for instance, without a teacher hovering over them to tailor their lessons.
Unfortunately, this doesn't work in many classrooms because the teacher has to manage too many different students learning at different rates and can't tailor the lessons appropriately to all of them at once.