Chemistry‎v3.15

What changed

• MonetizationWinter Sale offering lifetime premium access for a one-time fee of $4.99
• RetentionNew achievements system to encourage test completion
• New featureIntroduced mentors with selectable review styles: Strict Coach or Friendly Guide
• ContentAdded New Year visual theme
• UXAdded new animations to the user interface
• ContentAdded new data tables
• UXFixed various typos

Original release notes

Winter Sale — Premium access for just $4.99
No subscriptions. No limits. Forever.

Solving tests is now even more enjoyable:
 - new achievements: Zero, Draftsman, Expert… can you collect them all?
 - mentors are here — choose your review style: Strict Coach or Friendly Guide

Coming back feels better:
 - New Year theme
 - new animations

Keeping quality high:
 - new tables
 - typo fixes