Once they had come to the end of their abilities, the kids seemed to be content with watching me finish the later levels.

Certain parts of the game are not available from the beginning and they get unlocked at later levels.

In later levels, a smaller white submarine appears which also cannot be destroyed.

It's a really good game and the later levels get pretty difficult.

But a few details are different, especially in later levels of the game.

The later levels take concentration, fine control of your entire body, and a clear head.

Several of the later levels actually take place in the Chinese hell.

At the later level, scrutiny of 'what counts as education' is necessary.

At the end of each "Chapter" is a boss, which must be defeated before moving to later levels.

Material from later levels was visible on the surface when first discovered.