I've noticed that you've repeated item number 1 so there should be 7 items listed in your list.

At the first #1: This I agree on. If the player can come up with additional challenges on their own for this game, the player could then be playing the game longer trying to accomplish those additional self-created challenges.

At #4: I agree strongly in this as well. The game "Croc 2" has a horrible camera control, almost the worst I've seen. The modern Sonic games also have a fairly bad camera when it comes to playing as Sonic. Oh, and isn't it using the arrow keys for moving around? Up to go forward, down to go backwards, and left and right to turn? Of all the games I've played, it's always the arrow keys that are used to move the player around.