Monday, December 27, 2010

Holiday Hiatus

The year-end is a time for permissible indulgence, reflection and finishing all the things you've been putting off. For me, that means finishing a game project I've been delaying for too long. Inspired by the game jam we had at Klei the last few days before the holiday, I'm hoping to apply newly acquired XNA familiarity to get this wrapped quickly. I'm also planning a month-long series of posts starting in January, so I want to start that ball rolling.

So hopefully your Xmas game bounty is providing copious mirth and New Year's is looking to be the start of a fantastic year. See you all in 2011!


Monday, December 20, 2010

Dashed Upon The Rocks

I haven't written much about Super Meat Boy, but it's not because my fingers and hands are too ruined to type (although that's nearly the cause). It's a fantastic experience, basically the Platonic platformer, I just didn't have anything to add that was more substantive than "Yeah, it's really good."

Earlier this week though, I was listening to Jorge and Scott's conversation about grinding and it reminded me of something Kirk wrote about "skill grinding." Jason linked that piece and referred to it in his review of SMB for Paste (and thus the circle is complete). What Kirk calls "skill grinding" is basically referring to progress in a game that emerges not from a character earning experience points and gaining levels, but from the player themselves actually getting better at the game's challenges. Character improvement vs. player improvement. Kirk was writing about this in the context of Demon's Souls, but it applies even more so to SMB.

What I think SMB illustrates is games about player improvement operate best when the loop of the player attempting a challenge, failing and being able to try again is as tight as possible. In SMB, you barely have time to angrily sputter a new concoction of profanity before you're back in the fray. This allows the player to dash themselves again the rocks as much as possible, and while that sounds frustrating to some, it's actually the best way to improve. The frustrating part isn't failing, it's waiting to try again. Or worse, it's being forced to overcome a previously surpassed challenge just to reach the one in question simply due to arbitrary checkpointing. The satisfaction and improvement comes from analyzing the situation, attempting a solution, seeing what didn't work, refining it and trying again. Anything that sits in the way of that will make player improvement slower and less satisfying.

Of course, putting up barriers to player improvement with intent and purpose can actually be used to good effect. As the game that inspired Kirk's discussion of this topic in the first place, Demon's Souls certainly doesn't have the tight loop that SMB does. And failure in Demon's Souls is far harsher than SMB, where death is swift but relatively without consequence. As such, Demon's Souls feels far tenser than SMB, with much higher stakes. The only time I've found SMB to be particularly tense was a few of the longer levels near the end and when I finally neared unlocking The Kid. Demon's Souls plays the player, asking them to constantly weigh banking the souls they've got versus pressing on for more. Demon's Souls isn't superior to SMB or vice versa, but I'd wager more people could pick up and improve at SMB. Demon's Souls demands a certain ... dedication.

In the opposite direction, games that communicate progression of a character do so through lengthening the loop between moments of progress. Character progression is all about contrast. Progress that comes too quickly muddies the waters, making it so the moments of progress seem less impactful and distinct. Again, this style of progress isn't inferior to player improvement, merely different. Mass Effect 2 uses it quite well, going so far as to decrease the number of skill points you gain at each level. It certainly feels like fewer than Mass Effect 1, and the parade of "SpaceCorp Gun I-VII" is largely toned down as well. Whenever your Shepard progresses in Mass Effect 2 it feels substantive.

The trick bit with character-based progression is that it's easier to abuse than player progression. Turning the reward progression into an ever-increasing time commitment that offers little in return otherwise is dangerously nearing Skinner Box territory. And many free-to-play games make showing up really the only condition for success, but if that success still isn't coming fast enough, you can pay to increase the rate of reward.

I'm not going to say one is better (some of my favourite games are RPGs that are primarily about character progression), but there's something that feels very "tactile" about player progression in games. It's a manufactured skill you're improving, but honestly, you have learned to do something better. It's a made up something, but is it any more arbitrary than, say, juggling? I'd like to see more player progression games with a feedback loop as tight as Super Meat Boy. We've seen plenty of strong character progression games, but the trick bit with them is they almost always need something else to lean on to stay engaging (Mass Effect 2 as a pure shooter would be ... lackluster). Creating a great story or expert pacing is hardly a given for many studios, even very competent ones. I'd love to see more folks experimenting with player progression games instead. As SMB demonstrates, this kind of satisfaction is hardly played out.

And of course, the player-character progression dichotomy is only one axis a game can be satisfying on and it doesn't need to be particularly prominent in all games. And it's certainly a spectrum (multiplayer games with level advancement blend these things interestingly, and I might have more to say about that in the context of Assassin's Creed: Brotherhood). But I'll drop a stake to say player progression works best with a tight loop and character progression works best with a lengthy. Deviating from this can be useful, but it should be intentional. And it should certainly never be a punishment. I don't think many favourably remember Too Human for exactly that reason.


Wednesday, December 15, 2010

On Probability

Nearly everyone has a poor grasp of probability, including many professional game creators (and I very much include myself in this). I talked about procedurally generated content in games with some other designers tonight, and obviously randomness factors into that. And of course, chance in general plays a big part in many games. So rather than something more abstract, or about some game I've been playing lately, this is going to be a brief primer on the mathematics of probability. It's more that writing it will hopefully lodge it more firmly in my grey matter, but if anyone else gets something out of this, that's great too.

The difficulty in really understanding probability is compounded by at least two factors. One, pure randomness almost never exists in nature, so having an event so controlled and discrete as to have the probability of its outcomes even be calculable is tremendously rare. Even devices we manufacture to be random turn out to be quite biased (e.g. the rounded corners of Warhammer-style dice make them almost twice as likely to roll a 1).

Two, humans are really good at pattern matching. Honestly, too good. Our brains are wired to seek out patterns, even when they aren't there. Appropriately enough, one manifestation of this is called the Gambler's Fallacy. Basically this describes the belief that after a "streak" of one particular outcome, another outcome is more likely. So if you've been tossing a fair coin and it's come up heads twenty times in a row, tails is "due" to come up. But of course the coin has no statefulness or memory of past events. The likelihood of tails versus the 21st heads is the same as it always was, 50/50.

The reasoning behind most probabilistic math is actually quite simple. It's simply a matter of enumerating all the possible outcomes and either counting the ones you want or discarding the ones you don't. Using the perennial example then, what's the probability of a six rolling a d6 once? Obviously, 1/6. What's the probability of rolling two sixes in a row? It's just the likelihood of the first event (1/6) being following by the second event (also 1/6), or 1/36.

Other possibilities are slightly more complicated to explain, so I'll just mention one more common case and leave the rest to one of countless Internet explanations better diagrammed than this. Often we care about the likelihood of some event occurring at least once in some set number of tries. So what's the probability of at least one six in two die rolls? Well, the probability of not getting a six on the first is 5/6 and the possibility of that also being followed by a non-six is also 5/6. Multiplying these together we get the probability of no sixes occurring, so subtracting that from 1 gives the probability of at least once six. Probability = 1 - (5/6 * 5/6), or about 30.5%.

Note that it is not 1/6 * 2, which would be 33.3%. Seems like a small difference, but imagine this relatively mundane situation. Creating some RPG, our wayward designer sets up a quest where player must kill Greyfang Gnolls to retrieve a Stolen Senatorial Standard. Any gnoll has a 1/3 chance of dropping the standard. Thinking it would be appropriate to add "twice that many" gnolls, our designer puts 6 gnolls in an area, thinking almost all the players will get the standard by the time the sixth gnoll is dead. But what's the actual probability of the standard dropping after killing six gnolls?

As above, the probability of the standard not dropping is 2/3. Multiply that by itself six times for all the gnolls and subtract it from 1, or p(standard drop) = 1 - ( (2/3) ^ 6) = ~91.2%. That seems good, except imagine if our designer's game is successful, netting one million players. Of them, about 88,000 will kill all the gnolls and never receive the standard. To them, this will almost certainly be indistinguishable from a bug, or at best, a misleading quest description.

That is exactly the danger of probability. Something with a high probability seems like "it should occur" except for some amount of people, it won't. Setting an event to occur at a very low probability still means some fraction of players will still experience it. We want probability to behave as if we're setting bounds on the likelihood of something occurring, but that's not how straight random events work. They're stateless (again, see the Gambler's Fallacy), which means the likelihood of all sequences of outcomes is exactly the same. You're as likely to get 20 heads in a row as you are 20 tails.

This is nothing new either. Old Dungeons & Dragons random loot tables would often include one or two absurdly overpowered items in the far upper reaches of the chart, acting as if putting the "Ring of Three Wishes" at 1/1000 means it's rare. For someone rolling on that table once, getting the Ring of Three Wishes is just as likely as any other thing on the chart. So one out of a thousand gaming groups would have to deal with an extremely unbalancing item. Given that hundreds of thousands of people might be rolling on the table dozens of times, it's far more common to occur that you might think just looking at the "1/1000" likelihood.

Even some very, very smart digital game developers have made this mistake. Team Fortress 2 had its random loot system revamped earlier this year, as they detail here. The key line: "Previously, we rolled randomly at intervals to see if you got an item drop. Now we roll to determine when your next item drop will occur." They changed their algorithm to provide what they really wanted in the first place, item drops to occur randomly within some bounds.

On DeathSpank, we initially made the same mistake. Loot drops were simply a flat random chance, but that meant a player was as likely to kill 50 greems and get a loot drop from every one as they were to kill 50 greems and never get a single piece of loot. (This isn't quite true, there were other factors in determining when to drop loot, but it was still a very real problem)

The solution I proposed and implemented was to change the model of loot drops from being basically a roll of the dice ("boxcars means you get loot") to drawing from a deck of cards ("ace of spades means you get loot"). The difference being the cards don't go back into the deck after they're drawn. You don't know when you're going to get the ace of spades, but sometime in the next 52 draws it's guaranteed. The most often you'll see loot is back-to-back (last card in one deck, first card after the shuffle) but in this case, there will be a 51 card gulf on each side. And in the inverse situation, the longest you'll go between loot drops is 102 cards.

Again, this is a gross simplification, but it's basically the chance we (and by the sound of it, Valve) made to make our random distribution of loot match the player's expectations. And that's really the heart of it- only on the rarest of occasions do we actually want true randomness. Possessing at least a basic understanding of probability is an important skill for almost anyone interested in creating games. Used correctly, probability can be a fantastic tool but used incorrectly, it can create some seriously unsatisfying experiences. Even with something as mundane as dice, things are not always what they seem. Many suddenly penniless Las Vegas visitors can attest to that.

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Monday, December 6, 2010

Si Vis Pacem, Para Bellum

I finished playing Fallout: New Vegas last Monday night. As so many have said, it's basically more Fallout. I'd put it on par with Fallout 2, where for me, Fallout and Fallout 3 are just a notch above. No major deviations from expectations, but there were a few things I really liked. And if you've played it, the picture above should be a healthy hint.

Obligatory spoiler warning: Fallout 3 and Fallout: New Vegas revelations of a serious calibre follow.

As a technical gripe and preface, I really hope Bethesda either scuttles or dramatically upgrades Gamebryo for whatever they're doing next. The engine is seriously showing its age. It does fine with the environment, but really falls flat on people. Not only are they, at best, individually unsettling but the engine seems very limited on how many of them can be in a space at once. Hitman: Blood Money had a fantastic scene in New Orleans with some extremely dense crowds. And it's over four years old.

In contrast, you hit the Strip in New Vegas and it feels so empty. It's been talked up by countless NPCs on your way there, but the place itself is terribly sparse. Upon entering the club portion of the tawdriest casino, supposedly the Strip's most popular establishment, there were maybe four patrons and the bartender. Oh, and two dancers awkwardly gyrating on a massive stage that totally dwarfed them. All the spaces in New Vegas feel very cavernous. And without sufficient NPCs to fill them, going to the Strip feels more like you're at a Tuesday night concert waiting for the opening act nobody likes to start.

I can't imagine this is intentional, but an engine limitation. And it's really exacerbated in the game's climax, where Caesar's Legion attacks the Hoover Dam. The entire game you're told Caesar has been massing his army for four years, waiting to overwhelm the New California Republic's defenders. But when the attack comes, how vast is Caesar's Legion? Hundreds? Thousands? Not even close. It's maybe 15 legionnaires. Underwhelming doesn't even begin to cover it. It's not even enough guys to field a professional hockey team.

Now I realize it's absurd to think the game could simulate a battle with hundreds of participants, but it also shouldn't tell me that's what is supposed to be happening! It could have been setup that Caesar sent the bulk of his legion across the river, diverting the NCR's forces and then sent in elite commando units to take the Dam under the cover of darkness. But there's not even an attempt to reconcile the tremendous gulf between what the game says is occurring and what is actually happening for the player. I can't say it's anything but disappointing.

And the worst part is, otherwise Caesar's Legion is fantastic. They're a great antagonist, one of the best I've seen in a game possibly in years. They're strong because Obsidian got two things with the Legion right that greatly contribute to them being designed as a strong antagonist. First, they have a real presence in the world and to its inhabitants. People are talking about the Legion (sometimes exaggerated, sometimes not) well before you ever encounter them. When you finally do, you come across them leaving the town of Nipton (a real place in California) after they've killed or crucified the entire populace. Then they disappear and you don't cross paths with them again for hours. It's simple foreshadowing, but so many games have antagonists appear two minutes before you defeat them and they're never seen again.

Second, Caeser's Legion is well realized. Using the Roman Empire provides a wealth of characterization that requires almost no effort at all. And rather than just slap plumed helmets and leather skirts on some NPCs, Obsidian did a good job drawing upon real Imperial Roman characteristics. The use of proper Latin pronunciation, e.g. "v" as "w" and all c's as hard c's (so it's "Wall-ay" not "vall-e" and "Kai-sar" not "Seeser"). Caesar's Legion doesn't have spies, they have Frumentarii (the actual Roman secret service). Even small details, like the description of how the Legion fought at the first Battle of Hoover Dam exactly matches the maniple system the Romans actually used to defeat the popular phalanx used by other powers in the ancient Mediterranean (at least until Marius reorganized the legions again in 107 BC, which ultimately contributed significantly to the downfall of the Roman Republic and the rise of the Empire). And Caesar fighting against a corrupt, oligarchical New California Republic and its Senate is hardly a coincidence. Using the Roman Empire as a cultural basis for their antagonist is such a good move for Obsidian because it makes the Legion feel distinct and foreign without needing to create an entire believable culture from whole cloth.

In contrast, The Enclave in Fallout 3 appear almost literally out of nowhere. They're just the Bad Guys that do Bad Things. If you've played (and remember) Fallout 2, you may be a little more aware of The Enclave and what they're about. If you haven't, they just seem like a slightly better equipped version of the Brotherhood of Steel with a tailor that digs the Third Reich. The only foreshadowing at all is the wandering eyebots broadcasting messages from President Malcolm McDowell. And while the final encounter with the President isn't bad, the Enclave really does come out of nowhere and they have little purpose beyond just "Be Evil."

Of course, I've always been into the history of the ancient world and took several years of Latin in undergrad, so I'm probably both an easy sell and more appreciative of the details than others. And I've recently been listening to an excellent podcast that covers the entire history of ancient Rome that I cannot recommend enough.

Aside from the technical shortcomings of the combat interactions with the Legion, the moral ambiguity in their actions is unfortunately torpedoed (yet again) by a heavy-handed, point-based morality metre. These systems make having any kind of grey area impossible. While the Legion's actions are undoubtedly harsh, they are (like the actual Roman Empire) welcoming and fair to those that do not resist Legion/Roman control. And the NCR isn't exactly a paragon of virtue. It's bureaucratic, corrupt and clearly far more interested in Hoover Dam for their own interests than for the Mojave's.

What boggles the mind is New Vegas implemented a faction-specific karma system with surprising nuance. Instead of single good/evil axis, the faction relationships understand the difference between mostly good/a little evil and see you as a "Smiling Trickster" and mostly evil/a little good granting perception as a "Merciful Thug." But the global karma system undermines all of this, especially with regards to Caesar's Legion, where almost every action nets you evil karma. It's unfortunate, because the opportunity to provide some good "ends justify the means" hypothesizing with regard to the Legion could have been very interesting.

One final note: New Vegas does the epilogue right. One of my favourite things about Fallout 1 & 2 is the lengthy epilogue that details the effect the player had on places they visited and people they met. This was jarring absent in Fallout 3 where the epilogue addressed only a few areas and even then, only briefly. The epilogue of New Vegas is remarkably detailed and satisfying.

New Vegas had the ingredients necessary to surpass the excellent experience Fallout 3 provided. Unfortunately, shackled to aging tech and unable or unwilling to scuttle design inertia, things didn't quite bake up right. As far as antagonists go, Caesar's Legion completely outshines The Enclave. I just wish it had improved that much in other aspects. It's still a great time, but is fated to be "Yeah, it's more Fallout" rather than "It's the best Fallout!"

Oh, and I can't believe there wasn't a quest named "Sic Semper Tyrannis." That's either marked restraint or a huge oversight. Not sure which is better.

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Wednesday, December 1, 2010

Limbo and Linkage

Laura Parker put together some very smart words for Gamespot about Limbo and how its success could inform improvements in AAA games. She interviewed Manveer Heir, Tom Armitage and myself as part of the piece and it really is good stuff. I think I may have linked it on Twitter when it came out a few weeks ago, but it took Tom commenting about it to remind me I'd never mentioned it here.

It's a shame that it is buried in a staff blog and not part of their main news feed, because this is the kind of writing that would actually make me want to read sites like Gamespot. Apparently Laura had to fight pretty hard for the piece too, so please, give it your eyes for a few minutes.

I finally finished Fallout: New Vegas and have been trying to put together words about it. But the swarm of holiday obligations and business and descended early this year, so that will have to wait until this weekend. Laura's article will have to tide you over until then. But I used the phrase "burgeoning payload" in the interview, so really, what more could you possibly need?