Makes sense. I've set up similar stuff in the past by using a combination of settings for completion tracking and restricting access. You must have completion tracking enabled for the course.
You can pair a Choice with an Assignment. The assignment access is restricted to only students who have selected the paired Choice. The Choice activity controls which activity opens up and permits access based on Completion tracking for the Choice set to Show activity as complete when conditions are met > Show as complete when user makes a choice. You can make each activity worth so many points and control access to everything based on the score being below a certain amount. Once they have have the right number of points/grade, access to any more choice/activity pairs can be denied.
by AL Rachels.