No worries, appreciate the feedback. Codecademy is aimed at beginners, we're focusing on experienced devs. HackerRank provides challenges, whereas we're promoting interactive competition.
It's somewhat reminiscent of RosettaCode or Project Euler, too.
I think this is much more fun than Codecademy.
More choice is usually a good thing, it's a pretty nice project and it's still early days so it might fit somewhere.