Culture is the ultimate "Hook" for Retention: I learned that users are more motivated by "cultural rewards" than traditional badges. By integrating K-Pop and K-Drama context, we transformed language learning from a chore into a hobby, which was the primary driver for our +80% retention rate.

Balancing Entertainment with Education: The biggest challenge was ensuring that "fun" didn't distract from "learning." I learned how to use a Progressive Disclosure design pattern, showing the entertaining content first, then gradually revealing the deeper grammar and vocabulary layers so as not to overwhelm the user.

Designing for "Micro-Moments": Through user research, I realized most learners use the app during commutes or short breaks. I pivoted the design to focus on Atomic Learning, ensuring every lesson, video clip, and culture card could be completed in under 3 minutes, making the app fit seamlessly into daily life.

Data-Informed Iteration: Seeing the 4.8 satisfaction score taught me the value of listening to community feedback. Early users found the navigation confusing, so I simplified the information architecture to focus on a "Content-First" feed, which immediately improved our session duration and completion rates.