It's a free game with IAP of $1.99 (i think) to unlock all the rest of the levels. They give you 4 levels for free and the last 27 you have to pay for. That's probably why TA featured it with a paid price, since that's the full game...
Yeah, my bad. The confusion for me is that it still doesn't show any 'top purchases' icon in the store, the way most IAP games seem to, and I hadn't noticed any upsell while playing? I guess it's not what's happening here, but it it got me wondering if it would be crazy to launch at free for a day, then go up to paid, or you'd just be shooting yourself in the foot by missing sales at your greatest moment of exposure.