Hi Rudl, that file was saved by someone who was using Rotation style: "Free rotation" which allows for twisting of the view more freely including tilting the "up" direction around. The setting for that type of rotation is under Options > View > Rotate/Pan/Zoom options > "Rotation style" at the top of the dialog.

If the scene was saved with a tilted view and then you load it with Rotation style: "Rotate around world z axis" (which is the default kind of view rotation), that camera tilt will remain and behave kind of weird.

To clear the tilt, you can go to Options > View > Rotate/Pan/Zoom options > "Rotation style" and set it once to "Free rotation" and then back to "Rotate around world z axis", the tilt angle will be zeroed out when you switch between rotation styles.

Another way to clear it is to go to Options > View > "3D View angles", and on that dialog set the "Tilt angle" field to 0.

Once you do either of those things you should see your more familiar view rotation afterwards.

- Michael