You earn crystals as you complete lessons. You can buy more from the Shop tab

Duolingo Plus lets you download lessons offline and removes ad. You can start with a 7 day trial

There are posts by other learners and mini "games" that help you test your skills

During login, it asks for your age, name, email and password

The curriculum is arranged linearly as a timeline with tests interspersed in between

Add friends to compete with. You can search by name or find them from facebook

Profile and settings

The splash screen is the logo on a green background

You have 5 lives. When you run out you can wait, practice, or refill by spending crystals

Mimo Premium in app purchase

Levels of gamification

Fine tuning transitions, pop up for out of sessions

Gamification: Toto Orchard