If it's copying the game its copying(Spellstone) properly then it might not be terrible but the horrid wasp nest of bugs is really concerning. Like they managed to completely miscode stun, Stun 5 should be stuns 1 target every 5 turns but the game treats it as stun target for 5 turns every turn. Invisibility simply does not work. Drain life will occasionally make the enemy undead and be able to live past 0 HP. Sometimes the attack line will skip over an enemy and treat it like its not there. Game doesn't recognize Patricia as a CodeWeavers Hero for the win with CodeWeavers hero quest. Burn doesn't properly stack. Curse is just weird since it doesn't amplify fireballs but it remembers previous curses and increases the amplification.
I also hate that Arena rewards are RNG and 1 common card is one of the potential reward pulls.