After getting to Sun God level on every part of the gauntlet, my frog got a cool new hat.
Additionally, getting to 2 million is *hard*. The best I've done is 1.67 million, finishing with 14 extra lives. From what I can tell, you need to never die AND break 950000 points. Without the bonus points from retrying levels, I'm only scoring about 900000 from the entire game, so that's 17 extra bonus lives, plus current frog and plus 2 extra starting lives... or only +1 million from lives.
I did completely clear the screen with a chain combo of six on one of the earlier levels. (Apparently this is an achievement in some versions.)