Can you learn complete spanish with duolingo?
Can you? Tell me in the comments below :))
I don't think there is any resource the you can use to learn "complete Spanish" or any other language for that matter. I'm don't think "complete Spanish" is a desirable or a possible goal. Nobody speaks even their own language "complete". And even if there were a hypothetical person who did, language is dynamic, so they'd have to work really hard to keep up.
A more reasonable approach would be to start by asking yourself what you want to do with Spanish. Once you have that answered, you can begin to figure out what level of mastery you need and what your priorities within the language are. Are you mostly interested in the spoken language, the written language, the history of the language, the etymology of the language, etc.?
Once you have all this figured out, you can then proceed to see how far duolingo will help you out towards meeting those goals. It will certainly be helpful. But you should look into other learning resources as well.
Plus, once you complete your tree, you'll be able to answer your own question. :)
No, you can't. You will acquire an A2 level if you complete it properly. Forget about being very proficient or bilingual.