Beringela's Blog

February 24, 2010

More gameplay configurations than atoms in the universe?

Filed under: Games — Tags: , — Pencel Games @ 7:22 pm

A strange fact dawned on us whilst balancing the tower defence game Horn Swaggle Islands.  During gameplay balancing we used a central “dashboard” where we could easily tweak the various gameplay parameters in one place.  These parameters were usually floats and held the enemy speed, strength, resistance to various types of weapons, the various weapons themselves, their costs, strengths, fire rates, turn rates and upgraded values for all of these.  We also had two separate upgrade paths; you could buy upgrades with money, but you could also earn experience points for kills, and these two upgrade aspects interacted.

If you have 14 enemy and weapon types, with between 10 and 20 parameters each you’ve very quickly got yourself upwards of 200 floats to tweak.  In theory each float could take a very wide range of values, but their meaningful range in the game is going to be less, let’s say 10 discrete values for the purposes of this example.  Perhaps some floats will range from 1.00 to 2.00, others from 50.0 to 60.0, but let’s assume there are always 10 possible distinct values they can have in between their upper and lower bounds that are useable in the game.

Mixing Desk

200 dials to play with!

We can now imagine ourselves at a large mixing desk with 200 dials, each with 10 discrete settings (we don’t allow any to go up to eleven).  As we tune and balance the game we can imagine ourselves twiddling the various dials, a little bit here a little bit there, until we find just the right setup.  But how much twiddling would we need to do, and which dials needed twiddled?

Well, if there are 200 dials with 10 values each, that means we can have 10^200 different settings on our mixing desk.  This is a 1 with 200 zeroes on the end.  This is when the strange fact dawned on us.  “Hold on a minute, this game has more possible gameplay configurations than there are atoms in the observable universe.  How can we possibly find the configuration that’s the most fun?”

We didn’t actually know how many atoms there were in the universe, we had to look that up, but it was true!  There are something like 10^80 atoms in the observable universe.  So that is a 1 with 80 zeroes after it.  This is one of those numbers that is so outside human daily experience that is is meaninglessly large, yet it is dwarfed by our mixing desk combo possiblity!

Our little game is nothing special in terms of tweak-able parameters either.  We don’t have anything like the number of dials that many other Indie games have.  It is just a sobering and interesting fact that there are so many possiblities.

As it turned out, we couldn’t and didn’t find the “perfect” combination.  Even if there was one, how would you know when you’ve found it?  We just ended up tweaking until we found one of the many passable combinations, and we shipped that!



  1. In my opinion, genetic algorithms offer an exciting prospect for automated tuning of gameplay parameters. However this is a difficult endeavour, since it requires both decent AI in the player role, and a fitness function that captures the idea of ‘fun’. Implementing this will be hard work, but the same technology can also be used for dynamic difficultly and procedural mission generation. It’s something I’d like to try in the near future.

    Comment by Starglider — March 1, 2010 @ 5:57 pm

    • That’s a fascinating idea, and would be loads of fun to play with. As you say, capturing the idea of fun would be non-trivial. Certainly let us know how you get on with procedural mission generation, I’d be interested to see the results.

      Comment by indiegamedev — March 1, 2010 @ 7:30 pm

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