[noduerme]

Thanks for the tips! I haven't normally redrawn as aggressively as you suggest. I'm excited to try all these strategies in practice, and it's enlightening as well to hear your thought process.

The secret level plays in endless mode. On the home screen of the game, tap the white arrow in the upper left corner to go to the credits page. Then return to the home screen and go to the credits page again. The second time there will be a sort of gear looking design next to the credits. Tap on that.

I don't know if there's a further easter egg to solving it but maybe you'll figure it out ;)