Superman Returns
18 Achievements
1,000
15-20h
Xbox 360
The Greatest Day
Play for a total of 12 hours.
30
How to unlock the The Greatest Day achievement in Superman Returns - Definitive Guide
You will get this achievement if you are going for the Frequent Flyer achievement, it will take a very long time after the game is done, so this will unlock more than likely before you finish the FF achievement.
or if you are not going to bother with the FF achievement, you can just simply leave your system on while in-game
or if you are not going to bother with the FF achievement, you can just simply leave your system on while in-game
Playing through the whole campaign which takes about 6 hours, and finding all the kittens, takes about three. When you leave the console on overnight to get the "Frequent Flyer" achievement, you'll get this one as well.