The course was great! I love the way Nab explains the meaning of the words with videos first so you can guess it before you get a definition. Also there are lots of examples of usage so it won't be another new word in your vocabulary you don't know when and how to use.
Videos are short and absolutely not boring, all the words are up-to-date and are among the most important ones. Nab starts with useful phrases like "What's up", "No worries" etc and goes to more complicated ones: adjectives (hot, lit, flakey), verbs (score, hook up etc) and nouns (dude, grub etc)
Any level of English is okay for taking this course - from Beginner to Upper Intermediate or even Advanced. But I recommend this course for those who don't know slang at all or have little knowledge, who has never been in a native speakers' environment for a long time or who has a small vocabulary in colloquial (informal) english.
Thank you Nab!