1. Eh, I guess I've never had to transfer save data between updates before so I wouldn't know
2. I may be stupid
3. Even with the calorie keys, if someone is disabled in such a way that they are incapable of being good at the game, it's possible that they'll never reach the first one at stage 16. Even then, it would still probably be very rare for them
4. Fair enough
5. Oooh, interested in seeing that in the next update