Most of the growing swell of collectible card games on the App Store share essential similarities. You use a pool of magic points to summon minions that do battle with one another.

Earthcore is a collectible card game that belongs to quite a different tradition. Its closest relative is rock, paper, scissors.

Oh sure, they're called Earth, Fire and Water in the game but the principle is the same. Players take turns laying out cards belonging to the these elements on a three-lane grid.

When all lanes are full, the elements get compared to see which cards win. Losers deal that cards risk value in damage to their owner. Ties carry over their risk to the next turn.

Stupidly simple

It sounds simple. It looks simple. It's simple to learn. In practice, it's anything but simple.

Little tweaks muddy the model. There's actually a fourth element, dust, which loses to everything. Cards have powers that allow them to move around, copy other cards, and turn creatures into dust. And there's risk, a neat mechanic that means more powerful creatures hurt you more if you lose.

It's not enough to make the game feel any more complex to learn. It's easily enough to layer on some tasty strategy.

It's simple, stupid

It helps that this is such an unfamiliar model. It took me a lot of tries against the easiest deck in the extensive single-player campaign to get the hang of what was going on.

Once you've cracked that you're ready for online play. However, unlike a lot of its competitors, the solo option in Earthcore is very good. It offers many hours of fun without dipping a toe into the shark pool of ranked play.

Yet another way in which Earthcore differentiates itself is presentation. This is a gorgeous-looking game, full of quality art and smooth animation. The effect is somewhat spoiled by some of the hammiest voice acting I've ever heard but hey, there's always the mute button.

The game plays at a much more sedate pace than most of its ilk. Sometimes that's a good thing, making sure you stop and consider your moves in the heat of the battle.

Other times it can rob the game of drama, especially when you get a lot of ties and the risk factor in each lane builds up.

Simply Stupid

For all the subtlety in Earthcore, that build up can sometimes cause games to completely collapse. The values sometimes stack very high. Alongside a damage doubler in the middle lane, it can easily stack enough to win a match all by itself.

That's not a problem in itself. It becomes a problem when combined with that basic rock, paper, scissors model.

It's not uncommon that you can't respond effectively to an opponent's play because, with only four cards in your hand, you don't have the right elements.

If that just so happens to fall on a high-damage lane, it's game over. Those times leave a bitter taste. If you lose, it feels unfair. If you win, it almost feels like cheating.

This isn't something you can ameliorate with better deck building. There's plenty of choice and some interesting combos to stack up, but most cards have to stand by themselves.

Things get more interesting when you can craft heroes - cards with multiple powers - but effective decks are more about balancing risk and elements than abilities.

While that won't please veterans of the genre, it's another thing that keeps the game very accessible. It can be nice to know you can just tweak your deck and keep playing, rather than needing to focus on a complete rebuild from a confusingly varied pool of cards.

Earthcore is arriving into a crowded marketplace against some strong competitors, and it might be easy to overlook.

That would be unfortunate though because, while not a perfect game, it's full of bright new ideas in a genre that badly needs them. For that alone, it's worthy of your time.