Apologies in advance for the length of this entry; there’s a short summary in the last paragraph if you’re pressed for time!

A few weeks ago, in a moment of extreme boredom, I stopped to watch the snooker player Stephen Hendry score the maximum possible ‘break’ of 147 points. (13 minute video.) Snooker is not the world’s most exciting sport unless you are a devotee, and I am certainly not a devotee. Yet with my game designer hat on, the game of snooker and the way Stephen Hendry had to play to achieve this score both become quite interesting on an abstract level.

Compared to most computer games, it’s very simple in terms of mechanics. To borrow one of Chris Crawford‘s elements of terminology, it only has one ‘verb’ – use the cue to hit the white ball at coloured balls, with the intent of ‘potting’ the coloured balls in one of the six pockets. But then several rules come into play based on which balls you hit and where they end up, dictating the score you get and whether you get another shot or not. Strategies naturally emerge from a player’s awareness of the rules, balancing need to score points with the desire to deny the opponent points. eg. by playing safety shots. Yet this all comes about when there is only one significant way to interact with the game. Compare that to first person shooters for example, where you often have several different types of weapon (allowing typically for both direct and indirect fire), consumable items for health and defence,  different stances/poses/actions to cross obstacles or use cover, and so on. RPGs are perhaps even more full of verbs; you might have melee combat and ranged combat methods, spells you can cast, items to pick up, potions to drink, people to interact with and talk to, horses to ride, maps to view, etc. These games are all well and good but it seems apparent that we can stand to learn something from examining how just 1 action can produce interesting gameplay.

Probably the main thing to take away from the games like snooker, pool, billiards, etc., is that the main action can be applied in slightly different ways to vary the outcome – adverbs, if you will. Choosing the direction to hit the white ball in is like choosing who to shoot at in an FPS, but you also get other choices here. You can attempt to hit the ball harder so that it travels further after hitting the second ball. You can also apply spin to the ball, making the white ball change direction after contact, or even sending it on a somewhat curved path in the first place. Such choices are too often absent in video games – you choose who to punch or to heal or to send a magic missile towards, but often the choice begins and ends there with the ‘what’, having no say over the ‘how’.

It’s apparent that once a player gets good enough to pot the balls quite effectively, they have to start planning ahead and looking to how they can not only pot a ball, but make it easier to pot a subsequent ball. Again, this is where the adverbs come in and the player will apply force and/or spin to attempt to not only pot the coloured ball they’re aiming at but to position the white ball effectively in order to pot the next. But there are trade-offs here, since hitting the ball too hard or with spin affects accuracy, and hitting it too softly might mean the coloured ball you’re attempting to pot doesn’t reach the pocket at all. You have to compromise your current shot a little in order to hopefully benefit your second shot a lot; but if you compromise your current shot too much, you don’t get that second shot.

A classic game from the 80s that had an aspect of this was Laser Squad (play it online here), forerunner of the X-Com games. A simple turn-based tactical squad combat game, you move soldiers around and shoot at each other. But when you shoot at somebody, you get a choice of either an aimed shot or a snap shot. The aimed shot is more likely to hit, but the snap shot takes less time and therefore gives you chance to shoot again or find cover. You had to weigh up which was most worthwhile, taking into account how many successful shots you thought you’d need to take down the opponent, how their distance from you would affect the chance of hitting them, how much ammo you had left, and so on. You knew you wanted to shoot the enemy, but there was an interesting choice in how you went about it.

Like many other abstract games such as chess, you can plan several moves ahead in snooker. But the combinatorial explosion in snooker is continuous rather than discrete and you never truly know exactly where the white ball is going to be for your next turn until it stops. This is an interesting property of any game that models physics, a system that is understood by players well enough to make broad predictions easy but exact predictions almost impossible. This allows for a sliding scale of competence as players get better at judging the outcome of their actions without there ever being a point of total mastery. (I hope to elaborate on this sort of gameplay aspect in a future post.) Games like Armadillo Run and Crayon Physics are very literal examples of this sort of mechanic, but there can probably be more subtle examples too.

Snooker allows for the possibility of combinations (4:38 to 5:14 in the original video) where you involve more than just two balls in the action, typically bouncing one coloured ball off another to pot one of the two. This is generally a more risky shot but sometimes is the only one on offer, or perhaps offers a potentially greater reward if successful. This sort of mechanic is a bit more common in video games, especially in fighting games where explicit combinations are very common, often giving you the opportunity to score more damage but taking longer and exposing yourself to more risk in the process. But it’s rare to be in a situation where you absolutely need to pull off the special move, and more often it’s better to keep it simple when losing. Would games be more interesting if occasionally you were effectively compelled to use the high risk, high reward strategy on occasion? The infamous decapitation attack of classic 8-bit fighting game Barbarian might not go down well with modern players who have little tolerance for such a severe penalty for making one small lapse of concentration, but in a player vs. environment game where the NPCs lack such fragile egos it could be an interesting and rewarding way for a player to snatch victory from the jaws of defeat.

Another interesting aspect I noticed in the snooker video was that the fact that the pink ball was not in the prescribed place on the table was considered quite important. Due to the standard initial layout and the routine of returning coloured balls to their spots, snooker players get used to balls being on their initial spots most of the time. A similar phenomenon could be observed in some first person shooters where the spawn location of weapons and health can form a crucial part of a player’s route around the map. But just as a good player must know how to play the pattern and get from one such point to another, they must also avoid being a sitting duck if the powerup has already been taken or the position is occupied. Expressed as an explicit yet abstract design mechanism, this is setting up a distinct pattern that is visible to players, while allowing it to vary. This gives players several levels of mastery; first, they learn where the items are; second, they learn the optimal routes between them; then, they learn how to improvise if something isn’t where they expect to find it or find it too heavily guarded, and so on.

Finally, snooker’s concept of a maximum break relates to the metagame. Once Stephen Hendry had reached 80 points, he had effectively won the game due to there not being enough points left for the opponent to catch up. Technically, it would be possible for him to lose, should he commit enough fouls that award points to the opponent, but in practice such an occurrence is rare enough that the current frame is usually conceded by the opponent once this stage is reached. However, in snooker it is common to play on until the current break finishes, even though the eventual score has no effect on the game in hand. Prize money was at stake here for getting a maximum break, and further cash is available to the player who scored the highest break of the tournament. Yet in actual terms of the rules the score in each break is essentially irrelevant. Something similar can be seen in things like secret areas in 3D explorer-shooter games, tracking how many kills in a row you have in Unreal Tournament, or seeing how far through Thief you can get without being seen at all. All these aspects sit somewhat on top of the game proper, but provide for an extra view on the same gameplay.

One interesting aspect of the break in snooker is that the score is largely independent of the quality of your opponent. This makes it relatively meaningful to compare them no matter who you play against. Computer games with a similar mechanic could have an online high score table, providing the score is accumulated against a standardised opponent or in a system where the opponent’s strength is less important. This takes the player beyond the individual game they played in and adds them into the set of all gamers who play that same game. This adds the asynchronous multiplay aspect that people like Ian Bogost talk about, and which seems likely to grow in popularity via web-based systems such as Facebook and Twitter. (This was done quite well in the form of play-by-mail games in the past, so it will be interesting to see if any of the techniques used there make a comeback.) XBox achievements work along much the same lines. And TrackMania is an example of a game that provides the typical synchronous multiplay when you race other players, combined with an asynchronous aspect in terms of the local and global rankings that persist from race to race.

All this suggests to me that a lot can be done with just 1 game mechanic. Although adding in extra mechanics and observing the varied dynamics that emerge from their combination is a perfectly valid route to adding interest to a game, more can be done with individual mechanics. Find some ‘adverbs’ to allow the player to make some risk/reward tradeoffs, possibly buying future success with increased risk now, or vice versa. Make outcomes understandable but not trivially predictable so that players can make plans and learn how to anticipate the outcomes. Attempt to provide ways in which the mechanic can be re-used or combined to offer high rewards or a difficult escape route out of a dead-end situation. Set up patterns and predictable situations that players have to learn, but vary them on occasion so that adaptability and resilience to change is a useful skill that can set the experts apart. And see if it’s possible to add some sort of scoring system that sits alongside the game, not necessarily influencing the gameplay directly, but providing metrics that players can choose to compare themselves on, adding interest and replay value.