This cute RPG-lite game is perfect when you only have a few free minutes of gaming time, but paying for progress is frustrating. Playable in small palatable chunks, it lets you explore an adorable kingdom while tapping your way to postal-carrier prominence. Gameplay couldn't be simpler; your Postknight moves automatically while you attack, defend, and heal with a simple icon tap. Things can get hairy, of course, as enemies become tougher and appear more frequently, but as they upgrade, so do you. All this is a ton of fun, so it's a shock when it suddenly ends. Basically all free-to-play games have pay walls, but Postknight's is so obvious, you could knock yourself unconscious running into it. Things ramp up nice and evenly -- until you encounter a boss you just can't beat. Taking the app's advice, you make more deliveries, gain more levels, and try the boss again -- with the same disappointing result. Quick as a flash, you find yourself out of gems (in-game currency) and "watch an ad" recharges. After that, all you can do is wait for your health to slowly recharge or pony up some cash. This, on top of the app's built-in repetition (there are only a handful of very similar delivery missions) turns the light, fanciful role-playing into outright work, and who wants that? In addition to hobbling gameplay with a blatant money bid, the app offers yet another turnoff: It crashes sometimes, forcing you to repeat the repetition. Still, there's some real fun here, and who knows? Future updates of Postknight could favor entertainment over earnings.