I actually mounted a short 4X scope to the slide of a top-eject Winchester 94 once. When the lever was cycled the empty brass would eject in front of the scope. It would consistently shoot 2" groups at 100 yards and the neighbor I did the job for who couldn't use the iron sights any more due to failing vision and didn't like offset scope mounts kept harvesting deer with it for several more years. Some bubba jobs might offend the purists, but they still get the job done.
The gun in the video is just too fugged-up for words, however!
I was working one day at the LGS. He hires several of the local fireman part time.
We were busy as hell selling rifles and scopes. I sold a rifle/scope and needed to get tools to mount it up.
Young fireman had a Ruger Mini ranch on the vise with a 1-4 Leupold mounted backwards. Customer was standing there watching him.
I quietly tried to tell him it was wrong. He got offended and loudly told me the big end always goes forward. He said he can see thru it fine.
So I went on my way and started mounting the scope I sold. He walked up and asked me was i joking. I just told him to move the magnification from 1 to 4 and he would see the problem