Implosion is a free download (at least, it is for Android). The free version is essentially a trial, allowing you to play the first 6 levels of the campaign repeatedly. But, the campaign trail only displays levels you've unlocked, plus the next unlockable level that's grayed out and unselectable. Since the game costs $10 USD, I'd like to know just how much gameplay there is for my 10 dollars.
How many levels are there?