I'll be honest with you, it's not bad, but I probably wouldn't have bought it if I had known just how much this game cheats. Sometimes, your card features (burrow esp.) don't activate for no apparent reason, and during certian encounters, the game seems to select the worst starting cards in your deck, rather than selecting randomly. I got suspicious and tested this by closing the game and trying an encounter multiple times, also trying various things to possibly effect RNG, and the variations in the cards were minute, and all produced were very similar.
To put it simply, it stops responding when I look towards the library. I'm not the only person with this issue, either.
