I downloaded Version 1.0, which is 76.5 MB, not 765 MB. It is free, and it installs itself directly to the Applications folder. The publisher is an online gambling games outfit. The app for Mac is a rework of an app for remote devices. As a former yoga instructor, I rate the 1.0 content as worthless.
You can upgrade to 1.1 for $4.99, at a robust 1020 MB. User reviews of the phone version were raves for portable convenience, but more discerning reviewers criticized presentational flaws in the program. There seems to be a lack of detailed concern for safety instructions in 1.1.
You can easily hurt yourself very badly by doing the postures in an uninformed way. If you want to do yoga postures, I recommend that any practice be accompanied by a DVD (not a book) at appropriate level of difficulty with detailed pointers on how to take the postures safely.
95% of the benefit is in the dozen or so most basic postures. Beyond that is just showing off.