Game Balance Through Evolution

Posted: May 12, 2011 in Game Design
Tags: , , ,
This post is mainly concerned with games in the genre of RPG, you know, games where you level up and get stronger over time. I can however imagine that the concepts can applied to other genres, its just that I haven’t really considered it too much yet, maybe I will in another post.
In my experience there are two main ways to balance the strength of enemies against the strength of the player. The first is to have different areas with enemies of different strength. A player can spend as much time in an area as they need, then when they feel they are strong enough they can move on to the next area.
The second way to balance is to have level scaling, so that every time the player gets more powerful, so do all the enemies. This effectively makes leveling up a pointless task, and in some cases the enemies will get more powerful per level than the player, making leveling up a thing to be avoided. Of course there are games that will have enemies in certain dungeons at set levels, while the world that connects them has level scaling, and other ideas that combine the first two.
The idea of game balance through evolution is closer to level scaling, but should provide more variety in enemy strength than level scaling usually allows. So will start with a simple case by imagining a population of monsters with only one gene, the HP gene, which is how many hits it can take before dieing. At the beginning there will be great diversity with some having very few HP, and some having a lot of HP.
In most RPGs a player has the option to run away, unless they are surrounded and have no way of escaping alive so the player will run away from enemies too powerful to beat, and will kill the weaker monsters. Over time enemies with lower HP will be wiped out because they will be unable to survive and stronger monsters will take their place. But that’s not all, random mutations will occur between generations, either decreasing HP, and make them less likely to survive and reproduce, or increasing HP making them more likely to survive. The diversity of the population should provide enemies easy enough for the player to beat no matter what, but the general trend is for monsters to become more powerful over time, just like the player.
Lets not stop there. Most RPGs have different elemental attacks like fire, ice, lightning etc as well as having monsters be weak or resistant or neither to these elements. In the time it takes for a player to get an ice, fire and lightning spell at level 1, he could get 3 levels in his ice spell and do more damage than a level 1 spell. So it wouldn’t be surprising to find a player that specializes in an element to do more damage.
All the monsters will have genes representing resistance to the different elements, and random mutations can also cause them to increase or decrease. If the player relies completely or mostly on ice attacks, we can expect all the enemies with low ice resistance to die out and those with higher ice resistance prosper. Maybe enemies with high ice resistance, but incredibly low HP might still be killed by the player, but we can expect that even enemies with moderate HP and a decent amount of ice resistance will send the player running. So the overall trend is for the population of monsters to become more and more ice resistant, until the player changes his strategy.
Now I’ve been speaking as if all monsters in the game are one population that evolves together. It would make more sense for there to be several species of monsters that evolve separately, and the interactions between these monsters would impact the way they evolve. A dungeon with a breed of monsters that has a really powerful fire attack, might force other monsters to evolve fire resistance to survive.
A serious problem with using this method is finding a good rate of evolution. If the enemies evolve too slowly it won’t have any impact on the game, but if they evolve too quickly the player will be overwhelmed. I think this post is long enough as it is, and I’m interested to see what other people have to say about this. If you know a game that uses a system like this, link it. If you know a blog post or article that talks about something like this, link it. Thank you.
Edit: I may not have been clear, but if anyone has any thoughts, good or bad on this pleases share them. I was hoping for some conversation related to this topic.

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Comments
  1. shamtest says:

    I can’t seem to access this page from my droid!

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