We're continuously adding new lessons very quickly (we just added quite a few more). As we add more, we will break them up into "levels". As it stands now, you can most likely learn all of beginner, as well as some intermediate. As we add more lessons, you'll be able to go all the way to "master" level.
Furthermore, if you want to move ahead, you can create study lists to build up your vocabulary. Go to any word/kanji in the dictionary and create a study list or simply add to your drills. You'll start studying and building your vocabulary and can learn every single word/kanji in the dictionary in this fashion. This would take you way beyond advanced in regards to vocabulary.