I don't know how the tests are structured and therefore what those levels mean in practice, but simply from the description on Wikipedia[1] I'd consider B2 quite enough of an achievement when it comes to learning a language:
Can understand the main ideas of complex text on both concrete and abstract topics, including technical discussions in their field of specialisation.
Can interact with a degree of fluency and spontaneity that makes regular interaction with native speakers quite possible without strain for either party.
Can produce clear, detailed text on a wide range of subjects and explain a viewpoint on a topical issue giving the advantages and disadvantages of various options.
