how much depth goes into making a good puzzle game

James recently had an aspiring designer come up to him and say, “Man, puzzle games are easy. Anybody could make a Bejeweled clone.” He wasn’t entirely sure how to respond to that. Stating that making a type of game is easy is something you never want to do as a designer. For one thing, it’s a misstatement. Making a good game is always hard regardless of genre. Making sweeping statements like that shows a lack of curiosity, plus it devalues a lot of people’s work and it demonstrates that you’re only examining games on a surface level.

James didn’t want to be too hard on him because well to be fair, this is a rather common attitude out there on the interwebs. He sat the guy down and walked him through an exercise that James often goes over with his students at DigiPen, and then we realize , “Hey, we could totally go over that exercise here.” Get yourselves ready. This is the first extra credits practicum. Kind of surprised it took us 74 shows to do one.

To get the most out of this episode, especially if you’re hoping to get into game design someday, I’m going to strongly recommend that you pause a lot and do each of these little exercises as they come up. Don’t worry. I’ll warn you and play a little music when it’s time to pause. For the rest of you who don’t feel like doing math right now, that’s cool. You’ll still be able to follow along. Oh, and before we start, I want to give a big shout out to our friends at PopCap. First, you guys are awesome and you make awesome things. Second, I hope you don’t mind me deconstructing one of your games here.

All right. Today, we’re going to go over the web version of Bejeweled 2 because I know everybody can access that for free. You can find it over on the PopCap site. If you are participating in today’s exercises, go start up a new tab, get it fired up, and load up classic mode. If you’ve never played Bejeweled before, pause us for 10 or 15 minutes and get the basic mechanics down. We’ll wait. First pause starts now.

“A slightly lazier designer who didn’t shuffle the board between rounds would’ve created a totally different and probably inferior game. ”
We’re back. Now the first thing to remember when analyzing a game is that as game designers, we are scientists. We engage in the scientific method. We find a question we want to explore, we form a hypothesis, we test that hypothesis against empirical data, and then iterate on that hypothesis based on how it fits with the data we’ve acquired. Let’s start with a question. How does Bejeweled 2’s leveling system work?

First, we need to form a hypothesis and then test that hypothesis against a real world data you acquired from playing the game. For example, you might guess maybe beating a level is determined by the number of moves you make on that level. When you make enough moves, you progress to the next level. All right, so you’ve got your own hypothesis in mind? Awesome. Now pause us and go test it out.

You’re back? Cool. How did it go? Was your hypothesis correct? You probably found that progressing through levels is actually determined by the player’s score. Now we need to dig a little deeper. We’re going to try to understand if there’s a purpose behind this system. The first thing we’re going to do is establish how many points does it take to complete the introductory levels? It’s time to collect some data ie. play some games. Pause this, go beat the first six stages, record your score, and come back. Go.

All done? Great. Now to those scores. I’m going to do something here you should never actually do and I’m going to round these numbers a bit to make the math easier for the show’s sake but you should never do that. Bad designer. No.

All right. On to the numbers. To beat level 1, it takes 500 points. To beat level 2, it takes 1,500 points. To beat level 3, it takes 3,000 points. Level 4 takes 5,500 points. Level 5, 8,800 points. Level 6, 13,200 points.

A designer should always be thinking about how the player experiences the game. How does the player experience those numbers? What would we have to do to our current data set to make it more accurately represent the player’s experience? Well the player rarely starts at level 1 thinking, “Oh man, only 13,200 more points till I reach level 7.” No, no, no, no. They spend much more of their time thinking how long until I beat this stage. Were going to have to take the difference between each level value to see how long it takes to get from one level to the next, much more useful than simply looking at raw point values required to get to a given level. Pause, do the math, and come on back.

You got it? Here’s how the numbers should break down. It takes 500 points from level 1 to level 2. It take a thousand points to get from level 2 to level 3; 1,500 points to go from level 3 to level 4; then 2,500 points from 4 to 5; 3,300 points from level 5 to level 6; and to get from level 6 to level 7 takes 4,400 points.

Now that we know how many points it takes to get between the first few levels, we can say it gives us a weird, slow exponential curve. Now what? How do we make this data useful? Well, let’s return to the player. What other system affect how the player experiences this system? Well of course, the scoring system. Now we have something else we need to get data on. How many points does matching 3 gems on any given level earn you? How about matching 4 gems on any given level? How about matching 3 gems and chaining into another set of 3? Pause, grab some data, come on back.

You got it? Awesome. Matching 3 gems at level 1 will give you 10 points. Matching 3 gems at level 2 will you 15. Matching 3 gems at level 3 gives you 20 points, then 25 points, 30 points, and at level 6, it gives you 35 points. We see that all other block combinations simply give a multiplier to this match 3 base score. How does the player experience the conjunction of these two systems?

To put these two systems together, we’re going to have to divide the amount it takes to get to the next level by the amount of points that a base match 3 will get you on any given level. Now you may ask why we’re doing that. What will the number we get out of that mean? If you guessed it will define how hard the level is, you’re dead on. There’s another important variable here. What helps define difficulty? Your losing condition. In Bejeweled 2 classic mode, what’s the losing condition? When you can’t make any more moves.

Also worth noting is that at the beginning of every level, the board is shuffled. I’ll leave it to you guys to piece out why on average, making a valid move in Bejeweled leaves fewer total valid moves on the board. Just assuming that’s case, the number we’ve now come to, the amount of points to progress to the next level divided by the base points on a given level tells us directly numerically how challenging we can expect the given stage to be. What’s amazing about this system is the level of control over the difficulty it gives to the designer. You can see it right there in our initial data set. PopCap took a vaguely exponential set of numbers, used a completely linear number set to smooth out that exponential curve, and then tweaks the numbers wherever play test told them that players were having a hard time or not being challenged enough.

For example, if you’ve been doing all the math with us up to this point, you may have already noticed that the increase in difficulty from level 3 to level 4 is much greater than for level 4 to level 5. This relatively complex system is totally invisible to the player. To them, it simply feels like they’re progressing since the system is built to continuously increase the amount the player is rewarded and make them feel empowered without breaking the difficulty curve. In fact, its this system that let the designers construct Bejeweled carefully hone the challenge curve, but this entire system is dependent on the lose condition and board re-shuffling it every new level. A slightly lazier designer who didn’t shuffle the board between rounds would’ve created a totally different and probably inferior game.

The really incredible thing is that you’ll see players who’ve played a lot of Bejeweled no matter causal, no matter how uninterested in strategic thinking, playing around with this system. Ask any long time Bejeweled player, and they’ll tell you not to use your special gems until you need them since they carry over between levels. If you ask them why, they’ll probably tell you, “Well, because it’s better,” without a word about the math going on under the hood. The math ensures that that’s the way things work, and it also ensures that they get a sense of that for playing.

Also, if you really want to know how deep this rabbit hole goes, answer me this. How much harder is it to make your first match on level 5 as compared to level 1? That’s correct. No harder at all but your road for doing so is vastly increased. This system is even designed to make you feel like a bad ass every time you get to a new level just by the way they combine their point system and their lose condition.

You can see the depth of thinking that goes into making a good game, puzzle game, or any other kind. The next time you hear someone trying to claim that building little puzzle games like this is simple, you will know better. Just for the masochists out there, here’s a little easy homework assignment for you. See if you can figure out what they changed in Bejeweled 3 or the Facebook version of Bejeweled and then see if you can figure out why. If you’re ever feeling stumped, just come back to the golden question: how does the player experience this?