help with deck building combat game

I have some difficulty grasping the concept of the game. You mentioned Final Fantasy and Munchkin which somewhat gives me a clue.

So you want players to manage parties of characters, not individual characters. So the strategy of the game will be about combining character abilities and special attack/items to face your enemies.

From what I understand, your heroes does not get shuffled in the deck. What you deck build is their abilities that can be used by the heroes which could be a good idea.

Now about buying monsters in opponent's deck, I quite not like the idea, why playing both the villain and good guys. One idea I had for rune age is that you have a deck of monsters, you draw X monsters and you need to face them. Or you draw by pushing, you luck, until you meet a party of monster big enough you think you could defeat. But the more you draw monsters, the better the reward, or the more chances to complete the dungeon.

Another idea, maybe dungeons are made of a stack of cards where the last 3 cards contains the boss. You must dig constantly in the decks and the player who reaches the bottom of the deck meets the boss. Maybe monster cards could be added at the top of the deck at the end of the turn.

Second, does players really have to fight each other, they are heroes, they are on the same side. Maybe the competition could lie by leveling up faster than the other party, or completing quests before the other players. The player with the most completed quests wins (or most VP on quest).

As for combat, why should you chose secretly how to attack and defend, it's too fiddly for no good reason. You could have a formation, like front row and back row, or even better, like in final fantasy I, the character at the top of the list get hit more often than the character at the bottom of the list.

You also don't want to place character in defense only, because they become useless. Instead, you want a game that promote team work. So maybe characters has various support ability to help other characters when you have not drawn the right cards in your hand. I strongly suggest you design the cards placed in the deck by combining abilities: ex: Fighter does jump slash, but is combinable with spell holy light cast by the priest, giving an added effect greater than if both cards were played separately.

I like the idea that all surviving monsters in a round simply does their attack and damage then the combat continues. Many system use this method, like the new D&D dungeon crawler games and Arkham Horror.

Leveling up could be done by using killed monsters XP value as a currency to add cards to your combat deck and returning monsters into the game.

For some source of inspiration, you could take a look at thunderstone, I don't really like the game but it fit with your theme, so you could get a few ideas from the game.

Hope it answer your questions.