Game Design - Challenging a player in an RPG-like game without removing easy cards

Question

I'm designing a card game that I'm implementing on the computer that mirrors some gameplay aspects of dungeon crawlers and RPGs. The player's object is to survive as long as possible from the onslaught of monsters, etc. in the dungeon, while getting stronger and more powerful. The way the dungeon is generated is by drawing one card from the "dungeon" stack per turn, this card represents a monster, animal, item, etc. found in the dungeon. As the player progresses through the game, he gains better abilities to fight the monsters and animals with. The issue becomes that the player then becomes too powerful to have any challenge (e.g. after progresses through the game for a while, the rats in the dungeon won't be a challenge). My question is, how can the player be challenged, assuming that any cards in the "dungeon" stack cannot be removed, and that the player must become stronger (e.g. not progressing is not an option)?

One solution I thought of would be a leveling system, where the player's progress is measured through levels, and upon attaining another level, certain, more challenging cards are mixed into the "dungeon" stack. This however would involve different card backs (theoretically not an issue in the digital implementation) which would give away the difficulty of the card the player is about to draw.

Answer 1

The core of the problem is that the monster cards are an additive difficulty O(n) or even less (O(1)?), while it seems the player's abilities increase faster, something like O(n^2), O(e^n), or O(n^log(n)).

The key is to figure out the curve you want both the player progression and the monsters to be at, and make them fit that curve. Don't just focus on the monsters - some overpowered or underpowered player abilities can also remove the player from the desired curve.

Various ways to increase monster difficulty:

• Increase stats of monsters based on strength of player
• Give different monsters ability to work together and complement each other
• Increase number of monsters per encounter based on player strength
• Add stronger monsters into packs of otherwise weak monsters if player is strong enough: 1 rat -> 2 rats -> 3 rats -> 6 rats -> 1 wererat -> 1 wererat + 3 rats -> ...

Answer 2

You could have a variable modify the difficulty of all challenges, and that modifier goes up based on how many cards have been 'drawn'.

EX: Keep track of cards drawn and put your challenges in "pools". Thus any monster, X, will show up from card draws Y -> Z.

This way keeps you from having to have a classic 'level' system, though one could argue the character's "level" would be the number of cards drawn by that point.

[EDIT]: To further explain - I'm not suggesting adding/removing challenges from the deck, but instead generalizing them and then having them be decided whenever the card is drawn. You would draw a "Monster" or "Monster type A", not a "Goblin" or "Dragon".

Answer 3

A possibility is that some of the dungeon cards include a global modifier to all traps and monsters. So you might draw that rat later on, but the dungeon has effectively leveled up that rat and given him better ways to hurt the player in the same sense that tabletop games offer templates to increase the strength of a monster.