To all you native speakers who help out, thank you! I can learn from this sentence because of you.
shouldn't it be "ist das..."? and not "ist was...."?
No, because "was" is a short form of "etwas" (something) here.
This sentece is an ellipsis; the subject has been left out.
where is the question mark??? to show that it is a question
It's not a question. As kyky said, it's a short version of "Es ist etwas ganz anderes." In colloquial speech, the subject (here: es) can sometimes be omitted.
I translated it as "This is totally different" and Duolingo said that only "That is totally different" or "It is something totally different" are correct? Would someone please tell me why?
Nobody really knows. It must be something like 'if i told you, i should kill you'. I had the same problem with many similar sentences until i got used to it. :-(
That's sad o.O
Es ist etwas ganz anderes = is it a good sentence as well?
why anders is inflected here