That's intended. All the syntaxes are moved to subpages (like templates), the styling now done through CSS. This is to make the main page source looks cleaner and easier to use. You now only need to specify the filename and caption.
If you need to edit the sourcecode, you still can do it in the respective subpages.
If you specify a video file in the file parameter, it only show an image as thumbnail. Once you click the image, it'll show the video in a modal (popup). Unless you specify an image file in the file parameter, you wouldn't got an actual image file there.
A quick check. In the old format. When you click on the video, did it open a popup or took you straight into the file page? If it's the latter, any chance that you disable script, use modal blocker or any other plugin on your browser?
About the styling, I wouldn't revert back to old design unless there's any usability issue. Honestly I can't replicate your problem in any of my browser. If there's actually a problem, I wouldn't expect the problem to be in the particular video file.