While the card sets are the key to victory here, how you use the cards provides the challenge. Each card in Cardaclysm has a value -- in gold runes -- that has to be paid to play the card. Run out of gold runes, and you're unable to bring anything more into the combat. That means a key to play is in finding the right combination of cards to use. For example, you can have a higher-level dire wolf (made by combining dire wolf cards), but if your enemy paralyzes your beast, and you're out of gold runes and can't cast a spell, you're a sitting duck. Cardaclysm does a nice job of easing players into the game, and then starts to ramp up the challenge, putting a strong emphasis on the strategic elements. And simply trying to run through a zone without stopping to pick up treasures along the way doesn't work well at all. What's more, exploiting the weaknesses of each enemy is key to your survival.
The setbacks are fairly obvious. When you encounter a monster, you have two choices: attack or flee. But unless you attack, you can't advance the game. The pathways are so narrow, you can't skirt past an enemy and keep going, and the loot you receive isn't thrilling. Plus, the save function doesn't let you make progress midway between checkpoints. You die or quit, sending yourself back to the last checkpoint, so everything gained in that realm can be lost. At least it's visually impressive, and while Cardaclysm is a game that tantalizes with a bit of eye candy, it puts its faith in the combat/adventure. Newcomers to card-based/turn-based strategy games will find themselves tested, but the game does have a nice flow that makes for an entertaining outing. Sure, you may end up scratching your head and replaying some battles looking for the right combination of creature and spell attacks, but that feels like the fun part of Cardaclysm.