Limited cards make fights surprisingly tense. You have to read the enemy, hold back the right cards, and decide when a counter or dodge is worth more than another hit. Companion magic can bail you out when things go sideways. One Hit Kill, Low DMG is already unlocked in the current version, making monster runs and boss fights much less of a slog.
Randomized dungeons keep the formula from becoming stale, while class changes give later runs a bit more room to experiment. A neat pick for anyone who likes card combat with light character progression and offline play.