"I never had any friends beyond a certain superficial level," he said.

I'd only agree with you on a very superficial level.

On a slightly superficial level, they have a lot to do with it.

Shock, yes, but not surprise, at least no more than on a superficial level.

Often they have lots of friends, but only on a superficial level.

First, the suggestions so far made have been on a superficial level.

Still, the moment was pleasant enough, if only on a very superficial level.

But often it seems that the Japanese people never really want change beyond the superficial level.

People in this city are very friendly on a superficial level, but can be difficult to get to know really well.

People here seem very friendly on a superficial level, but can be quite difficult to get to know personally.