LogFAQs > #972243183

Culdcept is basically monopoly + a CCG.

You go around the board claiming property by playing a monster card to guard it, then invest your points into developing it to make it more valuable. If you land on a property, you can either pay the toll or play a monster card to try to defeat the one guarding it and claim it as your own if you manage to win.

There's also a sort of a "stock market" system, where you can buy element gems which go up in value as properties of the same element are enhanced so you might be able to sell them at a profit later. Though this mechanic isn't really used in story mode until the second postgame storyline.

There is a ton of single player content in just story mode, and you can also set up free matches too. Especially considering how dirt cheap it is now.

Most of the paid DLC is cosmetic. The exceptions are Challenge From Hell, which is kind of an endurance match with a higher point goal that might be useful to set up for trying to get some of the in game achievements, and the free time one where it has a few more matches with some characters (although there's a lot of matches with them in story mode anyway).

I think there's some free boards to download too, so you might want to connect online at least once sooner than later to make sure you get them.