With this application help, you can get the Russian language a fairly complete understanding at the elementary and intermediate level. For the advanced level, the app will no longer be relevant. It uses detailed interactive exercises to introduce vocabulary, teach grammar and how to hold a conversation. The material starts at the beginning and builds logically from the alphabet to personal pronouns and basic conversational phrases. You may not find the app itself too flashy, but the variety of exercises makes learning Russian quite fun.
The app is for a fee. A month of lessons costs from 14 dollars, if you buy for a longer period, it will be cheaper.