Video (screencast): “Snowball” and “Engine” Games

Following is the text of the slides:
“Snowball” and “engine” games
Dr. Lewis Pulsipher
PulsipherGames.com
“Game Design” channel on YouTube http://youtube.com/LewGameDesign

Wazzat?
Snowballs – usually economic – occur when the player who is ahead, more or less inevitably continues to get further and further ahead
Like a snowball getting larger as you roll it through sticky snow
E.g. a game where you can research (or spend) to improve economic output, that allows you to produce more, which allows more research/spending, and so forth

“Engine” Games?
“Engine” games are all about providing the right inputs to get the best output
They are “natural puzzles”, exercises in optimization
An economic snowball game is usually an engine game, but there are other kinds of snowball games – the problem, though, is the same

More than Two Sides
Snowballs aren’t a serious problem in games for two or fewer sides
When one side gets the snowball rolling, the game should end
Whether by resignation or by the rules of the game
But we don’t have those options, generally, with more than two players
I do, in rules for a few point games that are multiplayer (more than two) wargames, provide for ending the game early if one side gets way ahead

Conditions
Snowballs can occur when:
1) the game is deterministic and there are no explicit catch-up mechanisms AND
2) there are few ways for one player to significantly hinder another
When someone gets ahead, then naturally he or she continues to get farther ahead

How to Prevent Snowballs?
1) Ways to directly hinder or harm another player (as in wargames)
2) Chance built into the “system” that could cause the leader to falter
But this is “leaving it all to chance”, not a good idea
3) An explicit catch-up mechanism
But many players dislike these
Any combination of these three are also possible

Wargames?
A well-designed wargame cannot be a Snowball
Because there are lots of ways to hinder other players
Two or more players can gang up on the snowball leader
But there are 4X wargames that become economic snowballs
Partly because other players don’t know it’s happening, so cannot react to stop it
Also computer Civilization (which is in many ways a 4X game)
(4X: Explore, Expand, Exploit, Exterminate)

Be Aware
Many games, by their nature, don’t suffer from snowballing
But “engine” games often do
It’s up to the designer to guard against this
If you keep it in mind, you can look for it, and do something about it

An aside: it seems players rarely play a game more than a few times these days
If that’s the case, the snowballing doesn’t become obvious
But you should always treat your game as though it will be played dozens of times

“Snowballs” that cannot be stopped are a design flaw. But not uncommon these days.