(READ DESCRIPTION) Indiana Jones "100%" in  

UPDATE: You can get the last 5 gems in Water World by using the starfish bouncing to the key, making this actually 98.14%. Consider this outdated.
This category is just getting the maximum amount of gems in the game, which I found to be 211, but more might be possible in the bonus room, as I haven't really messed around there all that much. Also, there might be a way to get the four gems in water world, but I haven't found one, and neither have any of the walkthroughs I looked at.
I need to go to sleep.