My daughter was given this for her first birthday. She'd had it about five minutes before she tried putting wooden bricks in it. This didn't seem such a good idea so we took the bricks away. She then tried plastic spoons.
Fortunately she can't push the based down to "set" the spring on her own and so she's only once actually managed to hit herself in the face with a hard plastic toy (i'd loaded it and she carefully took the soft frog out and put a truck in while my back was turned). So mostly this is a fun and safe toy. But is has the thrilling/terrfying potential to be used as a canon by a curious toddler.
For those who think that modern play is too safe and who fondly remember a childhood of lead action figures and bicycles without helmets they can leave their child alone with this toy to back in that nostalgia. Everyone else might want to surpervise their child carefully.