I'm trying to find a way to reward players without leading to a runaway victory problem.
This is actually for a dungeon crawl style co-operative game with separate self-contained encounters.
There is a somewhat randomized element for choosing encounters. The issue is that as players progress though different difficulty zones, they may find that some encounters will be tougher than others.
Now, I don't want players to come to an insurmountable challenge, but at the same time, if things are too easy the game would become boring.
One way dealing with this, is each encounter can have an optional challenge or 'hard mode'. Weaker parties may elect to do the standard encounter, while stronger parties can try the challenge.
Except the challenge needs some kind of reward, or what's the incentive?
Right now, the only things to reward with are treasure(equipment) or new abilities. Both of which could lead to a problem where the more rewards earned make getting more rewards easier, and this leads to a balance issue.
I may need to add a new game element, but I'm wary about adding complexity.
Another reward type is a 'key' to effect future encounters or unlocking other content, but again, what's the eventual incentive?
Maybe they can get access to 1-use items? (scrolls, potions) The idea being that the don't permanently overpower the players. Or maybe the challenges give advantages to only select parts of the game?
These are all interesting ideas. However, each is only relevant for players that are competing with each other, and the primary mode of this game is co-operative. (That's not to say that there won't be competitive modes as an option) So the players aren't going to be hurting each others' progress or be 'in the lead' in a strict sense. Rather, they are fighting the game itself (And the game is very story-driven, including story before and after each encounter, all they way to confronting various bosses. The game ends typically by defeating the last boss encounter).
So the runaway aspect is vs. the game. The difficulty of the encounters is sorted by zone, and also some difficulty scaling due to the number of players. But it is harder to scale vs. player level, and feels more artificial anyway.
The basic progression mechanic works like this:
Players enter zone 1. They do a couple encounters and gain better equipment and level up in order to be powerful enough to defeat the zone 1 boss.
Then they are good enough to take on zone 2. They progress through more encounters, gaining more skill and equipment, and take on the zone 2 boss.
Then enter zone 3, etc.
So each zone is calibrated to the expected level of character power. The problem is that players that end up doing all the 'hard modes' might end up with significantly more power than expected by the time zone 3 comes around.
But zone 3 still has to be able to accommodate weaker groups that didn't win any of the challenges, yet still provide a challenge for the stronger groups.