Friday, August 20, 2010

Random Chance and Luck-Based Gaming

Introduction:
My friends and I were playing Super Smash Bros. Brawl which, ever since the 2nd week of me playing Melee, I have always played without items.
At parties though, items will go on on occasion - but, after a few matches, I want to turn them off - due to the fact that when items are on, there is no real point to playing because you have limited control over the way the game is being played, and you have limited ability to judge what might be coming your way.

Basically, the game is less about skill, more about luck.

In this point I'll like to highlight why sure, a little luck tosses it up - but when it comes down to it, skill is the main ingredient in fun.

A Little Luck is a Little Good
Don't get me wrong - a lot of outcomes in each match are due to at least a little luck - even if nobody gets a critical hit, or rolls a random class.
An enemy rounding a corner, a little weighted spray - or the fact that you thought that your enemy would make one move - then he didn't think of this move at all and went for another? There's a fair amount of luck.

That said, skill will still weigh in a lot on these issues - complimenting them. If you position yourself well and are aware of enemy locations, you will be able to effectively battle the enemy around the corner. With better aim, you have a better chance of your spray hitting the opponents. With good knowledge of the game, you can use moves that, regardless of what the enemy is thinking, have a good deal of success.

So, in every well balanced game, there'll be a bit of luck - but skill will still affect the outcome of a match over luck entirely.

So, why on earth would you want to add more?

Why Skill Reigns Supreme
Skill is important in games, especially in ones where you compete against other players.
Many players get satisfaction from exacting a task with proficiency, and showing off just how much they have learned about the game and how to play it - even against computer opponents.
It builds the player's self esteem, and gives them the feeling that they are having fun.

Many designers have analysed this feeling - one in particular being Raph Koster, the author of "A Theory of Fun for Game Design", who argues that the experience of fun is derived nearly entirely from the experience of learning, and trying to perfect facets of a game's gameplay.
I don't agree entirely - but I absolutely believe that learning and gaining skill is extremely rewarding to players, and as such is a main element of the experience of 'fun'.

Repeat the mantra, learning is rewarding, and rewards are fun.

You Did What?
Another aspect of luck is the negative side, where players feel cheated if they are beaten through luck-based occurrences, which is fair enough.
One second, you're beating some guy down with a well timed sequence of moves, and, the next, he gets a lucky critical and you're down. Despite the skill difference, or how well you executed the attack, the luck trumped your skill in determining the outcome of the encounter.

That's bad - it's as if you might as well have just played Paper, Scissors, Rock with the opponent. And everyone hates Paper, Scissors, Rock.

Something that I see a lot of designers do is have little occurrences that can determine the outcome of an encounter - and justify it with the fact that it's only a 1%, 2% or 5% chance - but all this does is have no effect on most encounters (so why even include it), but make the ones that it does affect completely based on chance and rage-inducing for the player on the receiving end.

Do not do this.
As explained - it's useless (it doesn't achieve anything) and bad game design at the same time.
No-one even notices if you don't include staples of random events (crits, etc.) in your game. The only time I've heard someone say "That's odd there aren't any critical hits", is immediately before "and I love it!".

If you want to include random chance in your game, do not use "Low Chance vs. High Payoff" chance.
To ensure that your game is balanced and fun, use "Moderate Chance vs. Moderate Payoff" or "High Chance vs. Low Payoff" chance.

Triggers
To define Moderate and High Chance, I need to define Triggers.
A Trigger is simply an event, that can cause a random event. It's the event that causes the proverbial die to be rolled. For example if every time you shoot a bullet from your weapon, it can critical hit for 3x damage, shooting your weapon is that event's trigger.

A trigger's Trigger Occurrence Rate is how many times this event will happen in an encounter (or in a given time period) - and will affect the random chance co-efficients you use.
For example, if you shoot 10 bullets per second, and they have a 10% chance to crit, that's effectively one crit per second.
If you want this one crit per second, and your weapon fires on the half-second, you would give it a 50% chance to occur. It's as simple as that.

For this reason, it's hard for me to define what I would consider Moderate and High Chances.
I simply do not know the Trigger Occurence Rate for the games that this post applies to, as each game has its own balance, pace, and encounters.
That said, I generally aim to have my lower limits of occurence at 12.5% or 16.6% (1/8 and 1/6), as any lower and unless your triggers are occuring rapidly, there is a rather low chance of the event occuring and it falls in the reals of "not useful but really annoying" features.

Anyway, "Moderate Chance vs. Moderate Payoff" and "High Chance vs. Low Payoff" chances offer the following advantages:
  • You can more easily judge their effect on game balance.
  • Players will more easily judge their effect on encounters, and will adjust their strategies in turn.
  • Something that has a higher chance of happening appears to be far more useful to players than low chance occurrences.
  • Something that has a higher chance of happening is actually far more useful to players than low chance occurrences.
The first advantage is actually really important - as I too have falled for the "Low Risk v. High Payoff" trap before, and, I'm in the middle of rectifying it for Pokemon Universe.

In PU, a few Pokemon have some abilities that have a tiny chance of activating, but, could win a match. Put them all together (each Pokemon had a few of them each), and I realised that these could decide matches more than team layout and skill a lot of the time.
The scary thing is, I put them in the game a while ago and it took me this long to realise how bad it really was.

As a designer, it's so easy to say "Oh, it'll only have 5% of the time, that won't affect anything," and "That makes it just a filler", but - the amount of grief it could give your players is tremendous, and could make the difference between having a game with a skilled design and a possible competitive future - and a casual party game that isn't even fun at parties.

Higher activation chances increase the transparency of a feature's effect on game balance - making it more enjoyable for both you to work on and players to play.

Conclusion
So remember:
  • Games with few random parameters usually have enough luck in them as it is.
  • Skill should always trump luck in deciding the outcome of an encounter.
  • Gaining skill and learning is a rewarding experience for players.
  • Low Chance, High Reward feature often don't happen enough to affect balance, but when they do happen, annoy players greatly.
  • Use "Moderate Chance vs. Moderate Payoff" and "High Chance vs. Low Payoff" chances.
  • These chances are easier to factor in your balance.
  • These chances are easier for players to factor into their strategies.
  • These chances increase the transparency of your luck system, increasing the quality of the game.
And that's why I think you should turn items off in Brawl.

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