Good Student requires you to complete the Tutorial. The Tutorial can be reset in the Options menu located under the General tab. Completing the turtorial unlocks the Crystalline Crystal Skin.
Related Achievements[]
Good Student - Completed the Tutorial. You deserve a cookie!
Pupil - Reached Hero Level 10
Veteran - Reached Hero Level 30
Defender of Etheria - Reached Hero Level 70
Group Hug - Raised a Hero of each type to Level 70