Can anyone give a brief introduction to Unreal engine?
After 60 posts and 34 created threads you ask us what is Unreal Engine? 
Anyway: there is an official page answering this very question: What is Unreal Engine? Also wikipedia might help.
Unreal Engine is a terror organization founded by the CIA.
:)What I mean is that describe your understanding of Unreal engine based on your experience.
sure this is my view on unreal engine:
It is bunch of horses randomly running on great Thor pastures.
Every time you bump on one of them you will get kicked, hard.
Those horses form streams and packs so its quite easy to avoid them (as long as you follow chosen by horses path).
Events when i bump with some i call “kicking contest with a horse” you just cannot win that.
They form evil packs and if you dodge one kick from one horse, another one from pack is just about to kick you in da butt.
When you get more seasoned horse kicking contender, you slowly realize that there are invisible horses and even upside down camels that mimic horses.
Recently i spotted some rhinos, donkey and mules. I wonder if there is an elephant somewhere in middle that nobody dares to mention.
That is my view on unreal engine and coding.
So as long as you follow path that you are meant to follow, no horse will kick you, but moment you step from it watch your as being kicked.
The trick is to find correct path around every horse pack there, even those invisible packs.
Yes! Yes! Somebody finally gets it! Awesome! But it’s not horses. At least not for me.
It’s like I’m in a cage. A running moving cage. That never ends.