On iOS 10 or later, the deleted photos will go to 'recently deleted folder' first for 30 days. that is the reason why the storage is not cleared up

Ok, so if you go to albums you will have several folders. Camera Roll, Favourites, Videos, Selfies, etc. One of those folders is called Recently Deleted and will hold everything you delete for 24 (I think) days which means the photos and videos aren't deleted at all yet; they just got sent to that folder. If you go to the Recently Deleted folder and press Select > Delete All then they will finally be out of your phone. You can also use that folder in the future if you delete something by accident and you the Recover option instead.

You don't have to wait a month. Like korvus wrote, you can manually empty the folder. Just go to "Albums", which you can select from the bottom right, then find "Recently Deleted". You can delete all of them from there.

If you copied the photos and then you manually deleted them from your phone it's possible they're still in the "deleted photos" folder where they'll stay for about a month or when you manually empty the folder. It's a security measure to prevent you from deleting the wrong photo.

Maybe it is displaying photos from icloud or something.

Or recovery, or you accidentally did not delete it at all.

Lot of possibilities.

+1 to that. There are many really good adventure games out there that you could try, my personal recommendation is Technobabylon. Look it up.