Nothing at all.
If everyone came to breakfast at the same time, space is a little bit of an issue as the breakfast room seems to be a converted bedroom, but you could also have breakfast in your room and usually people come to breakfast at different times.
Location very good, about 6 or 7 minutes from St Mark's Square. Its a small hotel, but if you look at as many as we did before booking, you will find that most hotels are small in Venice. But beautifully decorated (in Venetian style) spotlessly clean. Bedroom was perfect size (only 2 of us) overlooked a courtyard at the back, so peaceful. Included a small dressing area between bedroom and bathroom which was very useful as it kept clothes and cases out of the bedroom area. Lovely fluffy white towels and a heated towel rail. Complimentary toiletries, plus kettle and complimentary tea, coffee etc. Small fridge / mini bar. We didn't take anything from the mini bar but did use the fridge to store some snacks. I mentioned my gluten free diet before arrival and they even provided some gluten free breakfast biscuits, a very kind gesture (no extra charge). The lady who serves breakfast is very sweet and keen to ensure you have enough. Continental breakfast with croissant, cheese, meats, bread rolls, yogurts, jams, butter, tea coffee, chocolate. There is a lift which worked very well, but the stairs wouldn't be a problem. The lovely ladies on reception spoke Italian, English and French and were exceptionally helpful.