Quote from KinkyOnly got a second before i leave for the pub but ill throw my 2 cents in quickly. You need to think about what youre trying to sell yourself as (assuming you have the eventual goal of working in the industry). If you're trying to be a level designer you really need to be showing map layouts so employers can get a feel for your use of space and flow.
Also, some people disagree with this, i was always taught to just show my best work. If the 12th project doesnt show something that you havent showed in the first 11 projects then it has no place on your portfolio. I never have more than half a dozen things on my portfolio. I dont expect anyone to look beyond that when deciding who to hire.
Thanks! This is really insightful, I always thought it was best to throw everything I made out there. But you made me realise that is not always the best tactic. Quality not quanitity I think the saying goes. Thank you for your feedback!