The removal of the small screws to get at the memory was tough. It looks all so easy in the video but these screws are really small and really hidden away. Otherwise no problem-also not in removing the top case of Mac Mini.
Dont remove those 4 screws connecting the 2 parts of the internal assembly completely. Just loosen them enough so you can lift off the assembly. A magnet screwdrive would be great in this case. I did not have one.