Achievement-oriented grading for a game design class

I just posted a draft course description for the game design course I described in my previous post. After consulting with my co-instructor, we agreed to incorporate achievement-based grading. This is my first time designing this "gamified" style of summative assessment, but I'm pretty happy with the results. We articulated twelve achievements:

Seeker

Find an educational museum game aside from those shared by the instructors and write an analysis of it

Dabbler

Play a game outside of the canon and write an analysis of it.

Reflective Practitioner

Create an artifact (such as an essay or video) in the last two weeks of the semester to reflect upon the semester's experience, explicitly drawing upon game design literature

Nigh Completionist

Play and write analyses on 75%–99% of the games in the canon (or their approved alternatives).

Completionist

Play and write analyses of all the games in the canon (or their approved alternatives).

Detail-Oriented

Visit the Indiana State Museum as a guest and write about the experience.

Explorer

Visit another museum as a guest and write about the experience.

Quality Assurance

Participate in 75%–90% of the prototype evaluation sessions.

Quality Assurance Expert

Participate in over 90% of the prototype evaluation sessions.

Reviewer

Make significant comments on five other students' posted game analyses or essays

Expert Reviewer

Make significant comments on ten other students' posted game analyses or essays

Socializer

Attend a game-related community event and write about it

The current draft states that earning ten or more achievements merits an A, nine is an A-, eight is a B, and so on.

There are three parts of the course that we did not frame as achievements: a short student research presentation, five iterations of prototyping, and a rulebook requirement for student-designed games. These three elements are necessary for the course to work, so instead of framing them as achievements, we incorporated letter-grade demerits for failing to accomplish them.

In our discussion of the achievement-based grading, we noted that it's very similar to contract grading: a student can essentially choose their level of commitment to the course based on the grade they want to earn. All of the student-created artifacts (including writings, designs, and presentations) are subject to both peer and expert formative evaluation—a reflection of the studio-based learning I use in my Computer Science courses.

As always, feel free to share your thoughts in the comments.

EDIT: See this post for a reflection on the efficacy of this approach.