Monday, April 22, 2013

Advancement, Progression and Pacing (Part II)

In Part I of this article, game designer and educator Ian Schreiber explains the reasoning behind using advancement, progression and pacing in games. In Part II, he discusses challenge levels in PvE.

Two Types of Progression 

Progression tends to work differently in PvP games compared to PvE games. In PvP (this includes multi-player PvP like “deathmatch” and also single-player games played against AI opponents), you’re trying to win against another player, human or AI, so the meaning of your progression is relative to the progression of your opponents.

In PvE games (this includes both single-player games and multi-player co-op) you are progressing through the game to try to overcome a challenge and reach some kind of end state, so for most of these games your progress is seen in absolute terms.

Challenge Levels in PvE 

When you’re progressing through a bunch of challenges within a game, how do you track the level of challenge that the player is feeling, so you know if it’s increasing too quickly or too slowly, and whether the total challenge level is just right?

This is actually a tricky question to answer, because the “difficulty” felt by the player is not made up of just one thing here, it’s actually a combination of four things, but the player experiences it only as a single “am I being challenged?” feeling. If we’re trying to measure the player perception of how challenged they are, it’s like if the dashboard of your car took the gas, current speed, and engine RPMs and multiplied them all together to get a single “happiness” rating, and you only had this one number to look at to try to figure out what was causing it to go up or down.

The four components of perceived difficulty

First of all, there’s the level of the player’s skill at the game. The more skilled the player is at the game, the easier the challenges will seem, regardless of anything else.

Second, there’s the player’s power level in the game. Even if the player isn’t very good at the game, doubling their Hit Points will still keep them alive longer, increasing their Attack stat will let them kill things more effectively, giving them a Hook Shot lets them reach new places they couldn’t before, and so on.

Third and fourth, there’s the flip side of both of these, which are how the game creates challenges for the player. The game can create skill-based challenges which require the player to gain a greater amount of skill in the game, for example by introducing new enemies with better AI that make them harder to hit. Or it can provide power-based challenges, by increasing the hit points or attack power or other stats of the enemies in the game (or just adding more enemies in an area) without actually making the enemies any more skilled.

Skill and power are interchangeable

You can substitute skill and power, to an extent, either on the player side or the challenge side. We do this all the time on the challenge side, adding extra hit points or resource generation or otherwise just using the same AI but inflating the numbers, and expecting that the player will need to either get better stats themselves or show a higher level of skill in order to compensate. Or a player who finds a game too easy can challenge themselves by not finding all of the power-ups in a game, giving themselves less power and relying on their high level of skill to make up for it (I’m sure at least some of you have tried beating the original Zelda with just the wooden sword, to see if it could be done). Creating a stronger AI to challenge the player is a lot harder and more expensive, so very few games do that (although the results tend to be spectacular when they do – I’m thinking of Gunstar Heroes as the prototypical example).

At any rate, we can think of the challenge level as the sum of the player’s skill and power, subtracted from the game’s skill challenges and power challenges. This difference gives us the player’s perceived level of difficulty. So, when any one of these things changes, the player will feel the game get harder or easier.

Written mathematically, we have this equation:

PerceivedDifficulty = (SkillChallenge + PowerChallenge) – (PlayerSkill + PlayerPower)

Example: perceived challenge decreases naturally

How do we use this information? Let’s take the player’s skill, which generally increases over time. That’s significant, because it means that if everything else is equal, that is, if the player’s power level, and the overall challenge in the game stay the same, over time the player will feel like the game is getting easier, and eventually it’ll be too easy. To keep the player’s attention once they get better, every game must get harder in some way. (Or at least, every game where the player’s skill can increase. There are some games with no skill component at all, and those are exempted here.)

Measuring the components of perceived challenge

Player skill is hard to measure mathematically on its own, because as I said earlier, it is combined with player power in any game that includes both. For now, I can say that the best way to get a handle on this is to use playtesting and metrics: for example looking at how often players die or are otherwise set back, where these failures happen, how long it takes players to get through a level the first time they encounter it, and so on.

[This article was adapted from Ian Schreiber's course, Game Balance Concepts.]

Ian Schreiber has been in the game industry since the year 2000, first as a programmer and then as a game designer. Also an educator since 2006, Ian has taught game design and development courses at a variety of schools, and on his own without a school. He has co-authored two books, Challenges for Game Designers and Breaking Into the Game Industry.

Thursday, April 11, 2013

Advancement, Progression and Pacing (Part I)

In Part I of this article, game designer and educator Ian Schreiber explains the reasoning behind using advancement, progression and pacing in games.

A lot of games feature some kind of advancement and pacing, even multiplayer games. There’s multiplayer co-op games, like the tabletop RPG Dungeons & Dragons or the console action-RPG Baldur’s Gate: Dark Alliance or the PC game Left 4 Dead. Even within multiplayer competitive games, some of them have the players progressing and getting more powerful during play: players get more lands and cast more powerful spells as a game of Magic: the Gathering progresses, while players field more powerful units in the late game of Starcraft. Then there are MMOs like World of Warcraft that clearly have progression built in as a core mechanic of the game, even on PvP servers. So in addition to single-player experiences like your typical Final Fantasy game, we’ll be talking about these other things too: basically, how do you balance progression mechanics?

Wait, What’s Balance Again?

First, it’s worth a reminder of what “balance” even means in this context. In terms of progression, there are three things to consider:
  1.  Is the difficulty level appropriate for the audience, or is the game overall too hard or too easy?
  2. As the player progresses through the game, we expect the game to get harder to compensate for the player’s increasing skill level because they are getting better; does the difficulty increase at a good rate, or does it get too hard too fast (which leads to frustration), or does it get harder too slowly (leading to boredom while the player waits for the game to get challenging again)? 
  3. If your avatar increases in power, whether that be from finding new game objects like better weapons or tools or other toys, gaining new special abilities, or just getting a raw boost in stats like Hit Points or Damage, are you gaining these at a good rate relative to the increase in enemy power? Or do you gain too much power too fast (making the rest of the game trivial after a certain point), or do you gain power too slowly (requiring a lot of mindless grinding to compensate, which artificially lengthens the game at the cost of forcing the player to re-play content that they’ve already mastered)? 

Why Progression Mechanics? 

Let's consider what is the purpose behind progression. What is it useful for?

Ending the game 

In most cases, the purpose of progression is to bring the game to an end. For shorter games especially, the idea is that progression makes sure the game ends in a reasonable time frame. So whether you’re making a game that’s meant to last 3 minutes (like an early-80s arcade game) or 30-60 minutes (like a family board game) or 3 to 6 hours (like a strategic wargame) or 30 to 300 hours (like a console RPG), the idea is that some games have a desired game length, and if you know what that length is, forced progression keeps it moving along to guarantee that the game will actually end within the desired time range.

Reward and training for the elder game

In a few specialized cases, the game has no end (MMOs, Sims, tabletop RPGs, or progression-based Facebook games), so progression is used as a reward structure and a training simulator in the early game rather than a way to end the game. This has an obvious problem which can be seen with just about all of these games: at some point, more progression just isn’t meaningful. The player has seen all the content in the game that they need to, they’ve reached the level cap, they’ve unlocked all of their special abilities in their skill tree, they’ve maxed their stats, or whatever. In just about all cases, when the player reaches this point, they have to find something else to do, and there is a sharp transition into what’s sometimes called the “elder game” where the objective changes from progression to something else. For players who are used to progression as a goal, since that’s what the game has been training them for, this transition can be jarring. The people who enjoy the early-game progression may not enjoy the elder game activities as much since they’re so different (and likewise, some people who would love the elder game never reach it because they don’t have the patience to go through the progression treadmill).

What happens in the elder game?
In Sim games and FarmVille, the elder game is artistic expression: making your farm pretty or interesting for your friends to look at, or setting up custom stories or skits with your sims. In MMOs, the elder game is high-level raids that require careful coordination between a large group, or PvP areas where you’re fighting against other human players one-on-one or in teams, or exploring social aspects of the game like taking on a coordination or leadership role within a Guild.

In tabletop RPGs, the elder game is usually finding an elegant way to retire your characters and end the story in a way that’s sufficiently satisfying, which is interesting because in these games the “elder game” is actually a quest to end the game!

What happens with games that end?

In games where progression does end the game, there is also a problem: generally, if you’re gaining power throughout the game and this serves as a reward to the player, the game ends right when you’re reaching the peak of your power. This means you don’t really get to enjoy being on top of the world for very long. If you’re losing power throughout the game, which can happen in games like Chess, then at the end you just feel like you’ve been ground into the dirt for the entire experience, which isn’t much better.

Peter Molyneux has pointed out this flaw when talking about Fable 3, where he insists you’ll reach the peak of your power early on, succeed in ruling the world, and then have to spend the rest of the game making good on the promises you made to get there… which is a great tagline, but really all he’s saying is that he’s taking the standard Console RPG progression model, shortening it, and adding an elder game, which means that Fable 3 will either live or die on its ability to deliver a solid elder-game experience that still appeals to the same kinds of players who enjoyed reaching that point in the first place.

[This article was adapted from Ian Schreiber's course, Game Balance Concepts.]

Ian Schreiber has been in the game industry since the year 2000, first as a programmer and then as a game designer. Also an educator since 2006, Ian has taught game design and development courses at a variety of schools, and on his own without a school. He has co-authored two books, Challenges for Game Designers and Breaking Into the Game Industry.

Thursday, April 4, 2013

April 2013: Leveling

Hi!  While my group at the HackAThon were discussing our game, we had a discussion about levels...  about whether or not we needed levels in the game.  For me, I automatically think a game has levels but there are games, even RPGs, without levels.  I can remember arcade games that would go on infinitely until you messed up.

But usually, a game has levels that get progressively harder and harder.  This topic is related to last month's topic of Pacing.  In a puzzle game, the later levels are supposed to be harder than the early levels.  In a RPG, new content is level-locked.  You can't learn something or go somewhere until you reach the appropriate level.  The level indicates your dedication to the game.  It's a way of comparing yourself to others and the act of leveling up gives you a feeling of accomplishment.

I jumped into the beta of Age of Wushu, which has been reported to be a MMORPG without levels.  It's what you called "skill-based," which to me is kinda like levels in that you have to learn the first skill on the skill tree before mastering more advanced techniques.  What are the advantages?  I guess you're customizing your play experience.  If you want that skill, you can go down that path and you can do it at your own pace.

What do you think?  Which way works out better:  levels or no levels?