Wednesday, July 17, 2013

Design (Part 6) False Choices


This will be a series of articles about game design, using the popular games DOTA and League of Legends as illustrative examples. The specific words, "Design is an Optimization" was coined by the design director of Riot. It means that to him, design is an iterative process of optimization.

Thus if some aspect of DOTA or LOL seems inferior or different to the other, it is because a conscious choice has been made by its designers – the trade-offs have been examined, the benefits judged more than the costs.


Games are fundamentally about allowing the player to make choices. We present the player with a scenario, and present them a variety of options - and the idea is, the more skilled you are, the likelier you are to pick the better option and thus have an increased chance of winning. This can be seen at every level of the game - from what heroes you pick, to what lane you go to, what items you buy, how you level up your character, and most importantly, how you participate in battle.

Choices are interesting if all of them are potentially viable at some point. For example, in Scissors-Paper-Stone, you have a choice of 3 actions, one resulting in victory, one in draw, and one in defeat, but you don't know which one - it's up to you to predict your opponent's move. A "False Choice" is choice that results in an optimal (victory) or sub-optimal (defeat) outcome in all possible scenarios - that's not a choice at all, it's just an illusion of choice. You have to choose it / avoid it all the time, so you might as well not have been given that choice. Identifying a false choice is actually harder than it looks, as we'll see later!

Riot have talked several times about the issue of false choices in their game, and they've done a remarkably good job of removing them. DOTA2 however...

False Choices in DOTA2

Clockwerk's skill "Power Cogs" is an example of a false choice in DOTA2.

Clockwerk's Power Cogs will damage and knock-back enemies that touch it

If an enemy walks into the outside edge of the Power Cogs, he gets damaged, loses mana, and gets knocked backwards, back to where he started. So why would anyone choose to walk into the Power Cogs in the first place? It's a 100% lose situation: there is no reason why anyone would do this, ever.

Let's see how some similar environmental hazard skills work, and how they avoid presenting players with false choices.

Jakiro's Macropyre will damage enemies walking over it

Jakiro's Macropyre - creates a damaging field of fire on the ground. It's another environment effect that you generally want to avoid, but you could have a valid reason for walking through it. Maybe you really need to get to the other side and are willing to suffer the damage to do so. A choice is given to the player, walking through the fire is probably a bad choice but it can situationally be the right thing to do.

Disruptor's Kinetic Field prevents enemy movement through it

Disruptor's Kinetic Barrier - creates a wall and prevents enemies from walking through it. Enemies touching the barrier are just halted - they don't receive damage or knockback. No choice is given to player in this situation, they are simply unable to walk through the wall.

To be fair, Power Cog's isn't designed specifically only to create the false choice that it does. It's primarily used to trap people inside it with Clockwerk (so he can kill them with Battery Assault). You can tactically force the knockback and life/mana drain effect on enemies by using it just outside melee range - not so close that they'll end up trapped inside with you, but close enough that when the Power Cogs spawn it pushes them away. In some far fetched scenarios, you could have your teammates use skills to push enemies into your cogs and cause them to take damage.

This problem of unintended false choices can occur very easily with environmental type effects and it's a surprisingly difficult problem to solve - for example, Void's Chronosphere is intended to trap enemy players within it, however, anyone else wandering into the field while it's up will also get frozen. This is a false choice, as there is no reason why anyone would choose to walk into it, but it's there nonetheless. There's no real way to fix this problem in this case, as that's thematically how the skill works.

Further discussion - why it's bad, how to avoid

Why do we even care if there are false choices in games?

One is the minimalistic school of thought - having choices increases complexity. But false choices don't increase gameplay, so there's no reason to have them. Either take them out (like the Kinetic Field as described) or modify them so that some choice / gameplay is preserved (like Jakiro's Macropyre as described).

The other is that false choices are an unnecessarily negative form of feedback. Competitive multiplayer games need to give players feedback on how they're doing, so they can get better at playing them. Most of the time we want to use positive feedback - rewarding the player for using a skill correctly. For example, getting Mirana's Sacred Arrow to connect will reward the player with special dialogue and a powerful stun on the enemy. A false choice like walking into Power Cogs or Chronosphere is a very negative form of feedback - it's basically the game telling the player "Why did you do that, you idiot?" At least if it was a potentially valid choice - like being chased by enemies and trying to run through the Macropyre instead of around it - and the player died - the feedback the player would receive would be more like "Maybe this wasn't such a good idea in this specific situation, maybe try running around it and see if it works better." You're basically telling the player he made an error of judgement rather than that he was just being stupid.

Karthus' Wall of Pain slows enemies that walk through it

A League of Legends redesign of those skills will probably involve deactivating the active portions of those skills and turning them into an inert barrier after the initial cast - essentially still preventing people from entering the Power Cog or Chronosphere area but not punishing people who do so by accident. League of Legends has a couple of champions who have persistent barrier type skills, like Veigar or Karthus, which punish the player for walking through them, but never to the point where it becomes a false choice. Karthus has the skill called Wall of Pain that will slow you when you walk through it, but at least you've still moved some distance in that direction so you might want to do that anyway!

Removing false choices makes the game more forgiving, as there are less ways to punish the players for misplays - this is especially important for newer players. DOTA2 may simply not have this concern, as it's designed primarily with veteran players in mind - they might actually like the fact that having mechanics like this amplify the skill gap between better and worse players, giving the advantage to the more proficient player.