Is there a mistake here? Room was not given as a word for Platz. The suggested words were space, square, or yard. I put yard and got it wrong.
Platz is, in general, the free space you have to sit or move. So if they translate it as "room", they think of the free room to feel comfortable. This sentence seems good for cramped spaces like on the back seat of a car or in a theater to assure your neighbour that you still feel comfortable.
Yard or square are a different meaning of the word Platz. It translates as the free (public) space between buildings. It often has been given names like "Ernst-Reuter-Platz" or something like that.
This sentence is more about the personal space you have, so yard was correctly rated as wrong.
Platz is square or place as such - if you say "I have enough place / space" is as correct as saying "I have enough room" - why is this marked as a mistake?
Yes but "Ist dieser Platz frei?" is used to ask if a seat is free in a restaurant. Hmm
Why not "I have enough spots"? I'm pretty sure I've used that as a translation for Platz before and it was accepted. Also, out of curiosity, would Platz be used if you were talking about cemetery plots?
"I have enough spots" would be "Ich habe genug Plätze" in the sense of already knowing enough spots to visit so you don't need any more suggestions.
"Ich habe genug Platz" on the other hand may be the answer if you and a friend are using the same tiny table, he is occupying more of the table and asks you if you need more "room". -> "Nein, ich habe genug Platz."
"the cemetery plot" would translate to "die Grabstelle" consisting of "das Grab" (=the grave) + "die Stelle" (=the place, the position)
"an Ort und Stelle" = "on the spot"