Like most reviewers pointed out, there's not much on the adult content side of things, but I personally don't mind.
Regarding the gameplay, you basically run a character through what feels like a static campaign map. You fight the same 3 bosses in the same order, and even the regular enemies you fight seem to be fixed. What's more, there barely seems to be a difference between the branching paths you can take. You get more than enough health and card upgrades, so the only paths of value are ones that increase your skill effect (which you should prioritize) or where a shopkeeper pops up (where you can spam refresh for card removal and fish for better cards if you're desperate). The balance of each deck is okay. You'll probably have no problem beating the campaign using each character so long as you abstain from picking cards you can't immediately use. Oppositely, you shouldn't bother paying coins early in to upgrade cards, since you'll have ample opportunities to for free, and you really don't need that many card upgrades to get the ball rolling. Speaking of coins, there's no point in going out of your way to collect or horde it. You can only spend it on the shopkeeper, and you only see her like 2 or 3 times per map. I suppose you can spend coins to refresh her inventory, but you don't need anything too fancy to make an effective deck.
What's keeping me from rating this 5 stars is that the gameplay has a solid foundation for a much larger game, but makes no effort to actually build on it. For example, there's no story explaining why a bunch of skimpy elves are trying to tame monsters and why they have to kill the shit out of everything else to do it. There's no explanation for why upgrades come in the form of tentacle sex. There's no explanation for why all three needs to get the same exact monsters. Like previously mentioned, you pick up more gold than you can spend and the experience is somewhat static. Certainly, it's better than average attempts at a deck builder I've seen, but it's nowhere as engaging as it could have been. The decision to lock characters and skills behind "levels" seems like an arbitrary one, mimicking another well known deck builder I'm sure other reviewers have mentioned. If this game was meant to be enjoyed as a light snack, all characters and skills should have been available from the beginning. New cards being gradually unlocked would have been fine, but for its current content, I probably won't play it more than once per character just to see how each deck works.
P.S. Character XP is based on score, which in turn is affected by many rounds you take to win a fight. Unfortunately, slow decks means much slower progress.