Can i create screensaver with engine?
If yes, then how?

I don't know, never tried, but I think that screensavers don't differ much from typical exe's, google for it

http://www.vb4all.pl/content/view/122/0/

There's article about it. It shows how to create it in VB but also shows how screensavers works! It's Polish site, but if you want, I can translate it into english when i will have some free time.