Interesting idea, decent execution, bland theme
RPG elements are minimal, really. In a non-zoomable, fixed isometric 3rd person view, you click on a baddy and your character attacks it.
The initial choice of character type only controls your appearance, starting abilities and equipment. Levelling up is a matter of choosing whether to increase your attack, your defense, or your hit points; there are no special attacks or abilities.
For an inventory, you have only four slots: weapon, armor, shield, and miscellaneous. There are various weapons that drop throughout the game.
City building is also very basic: people come to your settlement and, if you meet the requirements, you can build a house for them in your settlement. They will either provide a service for your city (such as food or weapons) or you can tap them to come adventuring with you. Later you can upgrade buildings, which enables you to advance your citizens' abilities as well. Perhaps the coolest thing you can do, eventually, is to train a dragon to guard your settlement.
Speaking of adventuring, you basically clear out a map of relatively generic baddies (orcs, goblins, skellies, etc.) and then you win. Clearing a group of monsters gives you some fame (fame is needed to recruit higher level townies) and occasionally secures a resource for your town (again, needed for certain townies).
Sometimes a group of raiders will come after your town, though you can turn this option off when you start the game. Another difficulty-inducing option is to have periodic "requests from the king" which you have to fulfill or else lose fame. Usually it is just "send me x amount of food." The ability to control the difficulty of the game is a bonus because there is no tutorial and not much in the way of on-screen instructions.
Gameplay is pretty smooth, though it is sometimes frustratingly hard to click on the target you want to attack, particularly at higher resolutions. Also the lack of a scalable UI at higher resolutions is annoying, considering that you can't zoom the camera and so are often straining to see as much as you can of your enemies.
What is most lacking from the game, in my opinion, is any semblance of a distinctive theme or storyline. There is no back story whatsoever: you are simply told that the King wants you to build a town in the Hinterlands. Graphics are not bad, but the art direction is somewhat generic, and the types of creatures you encounter are boilerplate fantasy.
All in all, Hinterland is a fun, if not particularly spellbinding game. Like many hybrid games it suffers from the fact that neither of its elements are particularly deep. If roleplaying and character building are your thing, you will be disappointed. If complex city building turns you on, you should probably stick to other Tilted Mill games like Children of the Nile.
Still, if you are looking for a low cost title that will eat up a few good hours of gameplay, you could do much worse.