Rootwork ($1.99) bills itself as a Sophisticated Card Game, but what that means is left open to interpretation. It isn’t a deck building game, a collectible card game or even a multiplayer experience. It’s a solo game about being lost in the woods and staving off fear while you find your way home.

Doesn’t sound much like a theme you’d expect in a card game, which are usually fixated far more on mechanical than thematic elements, but Rootwork succeeded at sending a shiver or two down my spine. It’s an unsettling game, rooted in mysticism and darkness, and the creepiness weaves its way into the mechanics of the thing almost unseen.

You play a character lost in the woods—a child, an elder, a teen or an adult to begin with. Two have extra benefits, two have major weaknesses. They are something like difficulty modes, and something like game’s one major source of variety.

You’re accompanied by a capricious force known as She. She can be helpful—her card is always in your hand. If you make use of her power, she’ll win a round for you outright. Every so often She will hurt you for it, though. That gamble is the central thematic conflict of the game.

To find your way out of the woods, you take your cards and visit Sites. These locations in the woods are milestones, and each character has a few milestones they need to visit before they escape. Find the right ones, clear them, and you’re free for another night.

In your way are Menaces and Sticks. You clear them by matching the colors of your cards with the colors on them. Menaces will kill you with fright if you fail to get past them. Sticks will fill your pockets, leaving you without any flexibility for forming your hand. All the while, time is passing, and the weather is against you. Each turn a weather card is used, and when they’re all gone, you’re lost. Fright alone can kill you, but so can staying out in the woods too late.

So you match your cards to menaces, staving off fear, loss, fury corruption and deception. You trace your path back from milestone to milestone. In the end, hopefully, you make it out alive.

In practical terms, this means a good bit of clever card management and a lot of luck. Most of the time you’ll need to manage your resources carefully, tucking certain cards into your pockets and knowing when to take some strategic damage. Sometimes you’ll lose because you just couldn’t draw the milestones you needed. Sometimes you’ll lose because every big bad menace will show up against you. Sometimes you’ll win because every single hand will go your way. Small hands and short games mean there’s a limit to how much variety you’ll encounter.

This is offset by the characters you have to choose from, and the way Rootwork manages progression. Your wins are tallied by character, and you unlock new cards at certain milestones. Playing the Adult or Child is distinctly easier than playing the Elder or Teen, but you’ll need to handicap yourself with the latter in order to unlock the next cards.

The flaw in that system is that the milestones are far apart. Twenty wins per character, up to a thousand times overall—it’s a lot to ask. The gaps are a little too large to keep the game interesting via progression alone, and the core game does need a little help with its hooks.

While you’re unlocking new cards, you’re also unlocking the story. Rootwork has a tale to tell about the malevolence of She who rules the Woods, and you unlock it piecemeal as you escape the menaces you encounter. It’s a dark and bloody tale, well-suited to this unsettling game.

If you don’t care about the story and you don’t care about progression, you can go ahead and unlock all the cards via IAP. The game cautions against this sort of cheating, and unless you’re going to be satisfied with the intrinsic motivation of simply playing, you’ll probably regret it. Playing with those regrets is all part of the theme, though. Like the terrible mistakes Rootwork will let you make with She, you’re free to ruin your own experience at will.

Ultimately the card game at the heart of Rootwork doesn’t quite uphold its thematic aspirations. It’s creepy, sort of, but not as unsettling as the rest of the package. It’s mechanically strong, but not strong enough to carry it through a thousand or more winning games. That’s not to say it isn’t worth playing. Rootwork is a game worth sinking into, but few will have the tenacity to dig down into its depths.