The short answer is yes..
It is generally object orientated..
But the main aspect is the premade routines.. (I think)
As a preMade "bunch of codes" it limitates users to the "buch"'s content..
I mean an engine is almost the opposite of language without limits..
Some engines don't give you direct access to shadows, in example, but it is remodable.. so you can code your own components for the buch..
Rudely saying, an engine is an opensource with a better looking..
Sorry if it doens't satisfy you, but that is all I did get when I used engines such as Irrlicht (the best free one I ever seen)..
The worst foe lies within the self...