[ibdknox]

There's a pretty big difference in audience in these two examples. Codecademy is targeting people who have no, or nearly no, experience programming and trying to turn them into programmers. CodeCombat's normal stuff appears to be in the same vein, but this specific challenge is something only a fairly experienced programmer is likely to solve. It's easy to place great programmers. Not so easy to take someone, make them a good programmer, and then get them a job.