Wednesday, 1 March 2017

Complexity and Simplicity

Complex rules in games are in general seen as a bad thing. If it is complicated to apply a rule at the table, then this makes playing the game difficult. Not that it makes the game difficult to do well at, but it gets in the way of actually playing the game.

Simple rules are in general a good thing, as they enable you to get on with the business of playing the game.

But this is different to the complexity behind the rule.

Making Simple Complex

A rule can be a complex implementation of a simple idea.

Knight Hawks is a cool game - space ships flying around the table top shooting each other. In the advanced game there are ten different types of weapon, and five different types of shield, and to attack you cross reference these to see the percentage chance to hit. All weapons have a range, some weapons can only be fired in certain directions, some only go every other round, some get 5% knocked off per hex distance. All of these rules are based upon simple - even trivial - concepts, but in practice the implementation adds so much complexity to the game that combat makes my brain hurt.

Making Complex Simple

Rules can also be simple implementations of a complex idea.

In Explore I wanted skills to increase in cost, based originally upon the skill points system from Star Frontiers. But it quickly proves difficult to count up all the points in total you've spent. Star Frontiers has a table with two columns - one for the points for that level, one for the total so far.

In addition I wanted the cost to rise exponentially, so +1 rank always meant a fixed increase in the amount spent, which meant making the rules more complex - but...

I realised that if I chose the skill points carefully, they could both be exponential and remove the adding up. If the points were 1, 1, 2, 4, 8, 16 etc. then the total cost is just the next number in the sequence. If you're fifth rank you've spent 1+1+2+4+8 = 16 points. So you cross off the points as you spend them, and the next number is the total.

Mathematically that's quite a complex rule, but it results in a simpler system.

Is Explore Too Complex?

Explore attempts to (in some sense) "abstractly model reality"; the rules are chosen so that as much as possible the rules give you a reasonably consistent and non-arbitrary result; if the rules have to be overridden to avoid the fiction of the game becoming nonsensical then they've failed.

To achieve this has (as those of you reading recent posts in particular can attest to) taken a fair amount of maths and hard thinking.

However - in the end all this has boiled down to a couple of tables in the game that aren't even needed in play most of the time. You know a giant has +8 damage because double height is +8 height, so +8 size, so +8 damage. A -6 Strength penalty on throwing a spear is -6 damage and -6 range, which is half range. The only lookup were double height=+8, -6=half range, and both those are from tables looked up in character or monster creation.

Obviously the rules are more complex than many games, but they are also far simpler than many games based upon far simpler principles.

To me, the rules add to the game, without dragging it down. Any rules that dragged the game down have been ejected unceremoniously (and there were lots).

Complexity Tradeoff

Explore originally had have two scales - one for Height/Length (doubles every +2) and one for Weight/Strength/Range/Density (doubles every +4). Later I added a third for Speed (doubles every +8).

My latest change means I now have five scales, so that is more complex, but what is the trade off?

In play the increase in complexity is negligible. If you're looking up Range, you look up the range table as you did before. How it is calculated doesn't really matter.

On the other hand denser projectiles now get a damage bonus, so you get a bonus for a lead sling shot.

It also has many knock on effects which have to be considered:

Weak characters now lose far less range due to their penalties - a -6 penalty halves the range rather than reducing it to one eighth  - which is both more fun and more believable.

Previously in On Archery I had double the range gives you a -6 penalty on to hit. Now due to the recent changes double range is +6 range categories. Hence +1 range equals -1 to hit. A very pleasing coincidence!

In On Archery II: Longbows I calculated
for the arrow with the furthest range (and fastest initial velocity) in the experiment, kinetic energy is reduced by root 2 approx every 140.6m (461 feet), which in Explore means a -1 on damage per 448 feet (nearest length category).
So I said that at max range the kinetic energy was halved so an arrow got -2 damage, which didn't seem enough to me. Now it is -6.

So the knock-on effects all have a positive effect on the game, for a minimal cost.