Korean Grammar Hack 1.0 + Redeem Codes

This app can help people study Korean grammar more easily. Instead of having to use a thick grammar book, you only need this app to master frequently-used grammar patterns.
This app is also a good reference for people who are preparing for Korean efficiency tests.
Free - Completely offline

Main features:
+ This app provides detailed explanation and a lot of examples for many useful Korean grammar patterns.
+ There is also a section called "Confusing grammars". In this section, the common mistakes that Korean beginners usually make are discussed (for example, irregular verbs, ? or ??, ...)