What 'Elements' -make a great level?

[AdrenalinDragon]

I'd like to propose for CCLP1 what we originally planned to do with CCLP3 but kind of couldn't because of the storyline and the back-referencing in some of the levels: make the difficulty peak at 144 ("the end") and have the bonus levels be true "bonus" levels, with less overall difficult challenges (147 notwithstanding).

Somehow, you could also perhaps link the story of CCLP1 to CCLP2 (Events leading to the first level of CCLP2: A Fleeting Memory)