You must understand that sleep alone will not help you learn a new language. A "learning Russian while you are sleeping" program requires practicing Russian vocabulary in two or three 15-minute sessions during the day. The lessons have to be repeated throughout the week and the same lessons are then reinforced when the student is sleeping.
You should know that when you choose any software that promises that you will learn Russain while asleep refers only to learning Russian vocabulary. Most "learning Russian while you sleep" programs allow a student to understand the vocabulary and the various sounds of Russian words but comprehension is difficult. The grammar aspect is missing from the "sleep" program. Grammar and comprehension usually emerges from interactive communication rather than one-sided learning. This is where the learning "Russian while you sleep" program seems limited.
It takes practice to learn a language. Russian is a difficult language. It has different word endings depending on the context of the sentence. There is the need to distinguish between masculine and feminine and neuter nouns, as well. There are changing verb and nouns and different adjectives that use feminine and masculine facets. While learning Russian vocabulary may be possible when sleeping, learning the basic and advanced linguistics of the language will require more. You can learn Russian vocabulary while sleeping. For grammar and pronunciation, you should opt for a more interactive learning experience.