Some people with autism find it difficult to use their imagination when playing games. When my brother was really young he really didn't know what to do with his toys. My mum had to teach him what to do because he would happily sit there staring at a particular part and do nothing else.
Lots of children with autism enjoy playing alone and find it hard to play as a group and play games where we pretend to be things, like 'cops and robbers'. My brother can become very controlling and we all must do as he says because he gets very upset if we don't. Again, he isn't doing this to be horrible or annoying, it's just that he doesn't understand what it's like to be someone else.
He thinks we all think like him so when we play games, he thinks we all want to do what he wants to which isn't always true! Because he doesn't know what it's like to be someone else, he sometimes doesn't know if he's upset me.
He also has problems thinking about things that happened in the past or things that may happen in the future. He only seems to think about things that happen here and now.
So, those are the three main areas people with autism have difficulty with - but there are others.