I love the Creality K2 Pro, it has never given me any trouble and has produced perfect prints since the beginning. One thing I’ve realized after a few prints, while I was doing some cleaning, this printer comes with a protective film also on the inner part of the glass door, it’s barely noticeable. I’m sure only a few people have realized it. It’s a lot more difficult to take off than all the other films, and the door handle needs to be unscrewed. I recommend everybody be very careful taking this film off, because if you pull too hard, you might unglue the hinges from the door. Please don’t use any metal tools like box knives, as you can scratch the glass . After you have taken this film off, you get a lot better transparency. Good luck!!! 
I’ve realized this is an anti-shatter film to protect the glass door, but I prefer to remove it as you get a lot better transparency and if the glass shatters it’s gone anyway, the difference is that it won’t fall in pieces, but it will need to be replaced.