First Level. Need tips and help! :)

Hey. This is my first ever level in UE4 and i could use some feedback!

All the assets used have been bought from the Marketplace.

I need help with:

The shadows makes the stones in the beginning all black, where before they were gray. How do i fix this?

Other than that, just basic feedback! Please be constructive!

Here is a video.

EDIT.
Did a lot of work. Here is a new and more up to date video: