Here is the full list of all 13 Rangi achievements.
Collect all pieces of Kuficha artifacts
Connect your first color line
Meet the Muziki Giant
Complete the world of Muziki
Complete the world of Sauti
Finish level 7
Finish level 11
Finish level 8
Finish level 17
Finish level 19
Collect all pieces of Tambo artifacts
Collect all pieces of Kuru artifacts
Collect all artifacts