Apologies if this has already been mentioned (I tried to search for Mr Do but the search said that each word needed to be 3 characters) but the latest update with the new protection has broken Mr Do.
When you collect all the letters, it gives you an extra Mr Do but one of the letters (usually the letter E) is cleared and all the others are showing as still collected, so the character from E appears randomly (usually on the top left corner) and when you manage to get the centre fruit (or whatever it is) then it plays the tune (very repetitively and annoying lol) and the only way the baddies will move is when you go very close to them.
After a few more levels, part of the maze turns black and you can't see what's been dug or not.
Shame really. I've done some videos of it and may upload them to YouTube in the very near future.