Wow, it took me almost a year to take care of this bug (to make it even worse, it turned out to be 10 minutes of work ), but I guess better late than never. Hamster Filer 0.6.5:Fixed the inability to overwrite directories. Tweaked the layout of the file details dialog.
@gidzzz reporting directory size in "File details" (via long press "Details") is broken: it only shows directory size (logical object), not total size of all its contents like it should. So i.e. it`s reporting 4kB size for directory filled with bunch of mp3 files. If You can make it to report not only size but more info about directory contents (number of subdirectories in directory, number of files in directory - just like stock file manager does) it would be great.