It'd be awesome if there was an option to print out 'lesson notes' - basically a list of all the new words and grammar - after each level :)
Oh! Modern times! Why don't just use notebook and pencil? Listening, hearing, speaking and don't forget writing are all very important parts of learning process. I'm not sure about the precise percentage that each has with final knowledge but few years back in some newspaper i read the article about learning. It said something that, for example, when you read you absorb knowledge with I don't know, let's say 50%, when you hear something it has better percentage, and so on. On that scale, writing is I think somewhere in the middle, so don't skip it.