Limbo may not seem too special today, but back when it was first released it was very unique IMO. I'd still really recommend checking out the full game though, because you haven't even begun to experience it with the short demo.
Inside is incredibly weird mate... it gets weirder the further you get lol. I won't say anything else about it in case I spoil anything, but I will say this... it was my favourite game of last year.