The offline player (I have only tried the Android version but I assume the others are the same) could do with some attention. There is no course search - if it is truly offline then it seems to want to download the course list prior to letting you access the content you downloaded. The courses that you downloaded don't appear in the same order as they are in the online course therefore if you download a "mastering" series you need to be online to see which order it is that you should be playing the offline content in and while the quick rewind on pause is great some of the time there should be a second button that doesn't do that so that you can pause while looking at the screen content and then continue.