Why Stealth Features Make Not A Stealth Game

After a lukewarm reception to Assassin’s Creed III following its release that some fear may have disillusioned some fans, Ubisoft went all-out in their marketing campaign for Assassin’s Creed IV: Black Flag, the latest in the series. As a fan of the series (and, incidentally, one who didn’t buy AC3 following the less than perfect feedback it got), I have no problem with this, and was intrigued and excited to see some of the features being implemented get put to use. However, one particular bit of promo material that caught my eye was the stealth gameplay walkthrough, which talks up the various stealth features employed in the game.

[Yes I am perfectly aware that this post is hideously out of date- I’m working through a backlog here]

Y’see, watching that video got me thinking about the role of stealth in the Assassin’s Creed games, and eventually led me to the conclusion that, at its heart, the Assassin’s Creed series is not a stealth franchise. I could justify that statement by pointing out the huge variety of stuff the game offers beyond stealth (free-running, the admittedly awkward ‘wait around for counter chances’ combat, and traversing the high seas spring instantly to mind), or by pointing out the extent Ubisoft is prepared to go to to ensure you don’t ever actually have to use stealth if you don’t want to- I mean for heaven’s sake, they’ve just announced a new mobile game based on Black Flag called Assassin’s Creed Pirates, which allows you to do all the sailing around and piratey things without any of the exciting running around on rooftops that made the game so popular in the first place. But this wouldn’t actually address the core reason behind the AC franchise’s non-stealthness- for that we must consider exactly where the stealth genre comes from.

To explain: every game genre is basically defined by a single, core game concept, a sort of combination of mechanics and the emotional hooks that get us to enjoy (or not, as the case may be) games of that genre. In an RPG it’s about the characters and your advancing skills, in a strategy game it’s about the concept of ‘playing god’ and dictating how a whole system works rather than an individual, and in a stealth game the core concept involves hiding. This central concept naturally extrapolates itself into a series of other features after a while. In many (but not necessarily all) cases, waiting becomes a core mechanic too, as once our protagonist has hidden from whichever bad guy is appropriate it would be strange for him to be able to move out of cover immediately- as Extra Credits said during their episode on the subject of stealth, the trick to making a good stealth game is to make waiting fun. Not only that, but a key part of making the experience of hiding compelling and fun is for the player to be able to use it aggressively to their advantage. Thus, protagonists in stealth games are also generally able to make highly effective sneak attacks on an unaware enemy, frequently one hit kills such as slitting the throat or the Dishonored choke hold.

Thus far, Assassin’s Creed is sounding very like a stealth game, and it’s true the games have always featured stealth gameplay heavily. The game’s most characteristic feature is, of course, the hidden blade, intended specifically for insta-killing an unaware enemy (with the option for a suitably dramatic dive throwing them to the ground for good measure), and in later games this can be adapted to allow an enemy to be poisoned, meaning he won’t die until you’re well out of reach of any blame. AC2’s introduction of attacks from ledges, hide spots and rooftops also expanded on this, introducing a new range of ways for a player to get into a killing position whilst remaining undetected. Not only does the series’ ever expanding array of hide spots help this, but they also give the option of helping a player to run away from a fight if they so choose, meaning fighting need not be the only option. But then again these features alone aren’t enough to make a stealth game: by way of example, Skyrim had a sneaking system that allowed for high-powered sneak attacks on unaware enemies, but is quite clearly an RPG with a few stealth elements rather than a true stealth game.

Thus, mere adoption of stealth gameplay features does not make Assassin’s Creed a stealth game, and it fundamentally is not one for the following reason: for hiding and waiting to become a game’s central features the player must have a reason for doing so; hiding must benefit the player in some way. Not only that, but the usually slower-paced stealth approach must some how become the more attractive option compared to a full-frontal assault, which from the start has the advantage of being faster, more direct and more exciting. One can attempt to railroad the player down this route by making the player instantly fail if they are detected (as the AC series has done on multiple occasions), but this is a clumsy way of doing things that fails to make the stealth experience more fun and only serves to frustrate the player as to why they can’t just rush in all guns blazing. In most true stealth games, the player is forced into hiding by making it the most favourable defensive tactic (ie the best way to stay alive), which is achieved by making sure they have relatively little health/armour/defensive ability so can’t really stand up in proper combat.

And this, really, is what distinguishes Assassin’s Creed as not fundamentally being a stealth game. The combat in AC games is frequently (and rightly) criticised for being formulaic and repetitive, and part of the reason behind this is that all AC characters are really good at defending. To block just about all incoming attacks merely requires the ‘high profile’ button to be held down, and if the counter button is pressed at the appropriate moment then almost every incoming enemy can be killed the moment they attack. If countering isn’t your style, then many a foe can be taken down by simply bashing the attack button, and as later games allow you to upgrade your weapons by the end this can result in a very quick death for any NPC foolish enough to get in your way. And all that’s presuming the player wants to stand and fight; even in AC1 enemies could be taken out from afar with throwing knives (which I suppose could be tenuously considered stealth weapons), and by later games our protagonist has grenades and a ****ing gun* at his disposal, which aren’t stealthy by any stretch of the imagination.

By making it so easy to fight, to cut through swathes of enemies with hardly a thought, the developers of Assassin’s Creed have ensured the focus of their game is not about stealth, and although this is by no means a bad thing (not every game need be stealthy) this fact does, I feel, somewhat undermine many of the stealth features they have chosen to include in their various games. Just so I can consider my point proven, some months ago the Assassin’s Creed Facebook page asked its readers which series was their favourite: Assassin’s Creed or Thief, the series that almost single-handedly invented the stealth genre and had recently announced a new game (the fact that this game has subsequently turned out to be terrible is, of course, an entire other point). How did these people, who I shall remind you were writing on the official Assassin’s Creed Facebook page, respond? Why, overwhelmingly in favour of Thief, of course.

This was, however, before AC4 was released.

*That list doesn’t even mention stuff like the hookblade and parachutes which, cool though they are, do nothing for the games’ stealth elements other than distract from them.

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Hitting the hay

OK, so it was history last time, so I’m feeling like a bit of science today. So, here is your random question for today; are the ‘leaps of faith’ in the Assassin’s Creed games survivable?

Between them, the characters of Altair, Ezio and Connor* jump off a wide variety of famous buildings and monuments across the five current games, but the jump that springs most readily to mind is Ezio’s leap from the Campanile di San Marco, in St Mark’s Square, Venice, at the end of Assassin’s Creed II. It’s not the highest jump made, but it is one of the most interesting and it occurs as part of the main story campaign, meaning everyone who’s played the game through will have made the jump and it has some significance attached to it. It’s also a well-known building with plenty of information on it.

[*Interesting fact; apparently, both Altair and Ezio translate as ‘Eagle’ in some form in English, as does Connor’s Mohawk name (Ratonhnhaké;ton, according to Wikipedia) and the name of his ship, the Aquila. Connor itself translates as ‘lover of wolves’ from the original Gaelic]

The Campanile as it stands today is not the same one as in Ezio’s day; in 1902 the original building collapsed and took ten years to rebuild. However, the new Campanile was made to be cosmetically (if not quite structurally) identical to the original, so current data should still be accurate. Wikipedia again tells me the brick shaft making up the bulk of the structure accounts for (apparently only) 50m of the tower’s 98.6m total height, with Ezio’s leap (made from the belfry just above) coming in at around 55m. With this information we can calculate Ezio’s total gravitational potential energy lost during his fall; GPE lost = mgΔh, and presuming a 70kg bloke this comes to GPE lost= 33730J (Δ is, by the way, the mathematical way of expressing a change in something- in this case, Δh represents a change in height). If his fall were made with no air resistance, then all this GPE would be converted to kinetic energy, where KE = mv²/2. Solving to make v (his velocity upon hitting the ground) the subject gives v = sqrt(2*KE/m), and replacing KE with our value of the GPE lost, we get v = 31.04m/s. This tells us two things; firstly that the fall should take Ezio at least three seconds, and secondly that, without air resistance, he’d be in rather a lot of trouble.

But, we must of course factor air resistance into our calculations, but to do so to begin with we must make another assumption; that Ezio reaches terminal velocity before reaching the ground. Whether this statement is valid or not we will find out later. The terminal velocity is just a rearranged form of the drag equation: Vt=sqrt(2mg/pACd), where m= Ezio’s mass (70kg, as presumed earlier), g= gravitational field strength (on Earth, 9.8m/s²), p= air density (on a warm Venetian evening at around 15 degrees Celcius, this comes out as 1.225kg/m3), A= the cross-sectional area of Ezio’s falling body (call it 0.85m², presuming he’s around the same size as me) and Cd= his body’s drag coefficient (a number evaluating how well the air flows around his body and clothing, for which I shall pick 1 at complete random). Plugging these numbers into the equation gives a terminal velocity of 36.30m/s, which is an annoying number; because it’s larger than our previous velocity value, calculated without air resistance, of 31.04m/s, this means that Ezio definitely won’t have reached terminal velocity by the time he reaches the bottom of the Campanile, so we’re going to have to look elsewhere for our numbers. Interestingly, the terminal velocity for a falling skydiver, without parachute, is apparently around 54m/s, suggesting that I’ve got numbers that are in roughly the correct ballpark but that could do with some improvement (this is probably thanks to my chosen Cd value; 1 is a very high value, selected to give Ezio the best possible chance of survival, but ho hum)

Here, I could attempt to derive an equation for how velocity varies with distance travelled, but such things are complicated, time consuming and do not translate well into being typed out. Instead, I am going to take on blind faith a statement attached to my ‘falling skydiver’ number quoted above; that it takes about 3 seconds to achieve half the skydiver’s terminal velocity. We said that Ezio’s fall from the Campanile would take him at least three seconds (just trust me on that one), and in fact it would probably be closer to four, but no matter; let’s just presume he has jumped off some unidentified building such that it takes him precisely three seconds to hit the ground, at which point his velocity will be taken as 27m/s.

Except he won’t hit the ground; assuming he hits his target anyway. The Assassin’s Creed universe is literally littered with indiscriminate piles/carts of hay and flower petals that have been conveniently left around for no obvious reason, and when performing a leap of faith our protagonist’s always aim for them (the AC wiki tells me that these were in fact programmed into the memories that the games consist of in order to aid navigation, but this doesn’t matter). Let us presume that the hay is 1m deep where Ezio lands, and that the whole hay-and-cart structure is entirely successful in its task, in that it manages to reduce Ezio’s velocity from 27m/s to nought across this 1m distance, without any energy being lost through the hard floor (highly unlikely, but let’s be generous). At 27m/s, the 70kg Ezio has a momentum of 1890kgm/s, all of which must be dissipated through the hay across this 1m distance. This means an impulse of 1890Ns, and thus a force, will act upon him; Impulse=Force x ΔTime. This force will cause him to decelerate. If this deceleration is uniform (it wouldn’t be in real life, but modelling this is tricky business and it will do as an approximation), then his average velocity during his ‘slowing’ period will come to be 13.5m/s, and that this deceleration will take 0.074s. Given that we now know the impulse acting on Ezio and the time for which it acts, we can now work out the force upon him; 1890 / 0.074 = 1890 x 13.5 = 26460N. This corresponds to 364.5m/s² deceleration, or around 37g’s to put it in G-force terms. Given that 5g’s has been known to break bones in stunt aircraft, I think it’s safe to say that quite a lot more hay, Ezio’s not getting up any time soon. So remember; next time you’re thinking of jumping off a tall building, I would recommend a parachute over a haystack.

N.B.: The resulting deceleration calculated in the last bit seems a bit massive, suggesting I may have gone wrong somewhere, so if anyone has any better ideas of numbers/equations then feel free to leave them below. I feel here is also an appropriate place to mention a story I once heard concerning an air hostess whose plane blew up. She was thrown free, landed in a tree on the way down… and survived.

EDIT: Since writing this post, this has come into existence, more accurately calculating the drag and final velocity acting on the falling Assassin. They’re more advanced than me, but their conclusion is the same; I like being proved right :).

The Price of Sex

This is (probably, I might come back to it if I have trouble thinking of material) the last post I will be doing in this mini-series on the subject of sex.  Today’s title is probably the bluntest of the series as a whole, and yet is probably most descriptive of its post’s content, as today I am going to be dealing with the rather edgy subject of prostitution.

Prostitution is famously quoted as being the world’s oldest profession, and it’s not hard to see why. Since men tend to have physical superiority over women they have tended to adopt overlord roles since the ‘hitting other people with clubs and shouting “Ug”‘ stage, women have, as previously stated, tended to be relatively undervalued and underskilled (in regards to stuff other than, oh I don’t know, raising kids and foraging for food with a degree of success often exceeding that of hunting parties, although that is partly to do with methodology and I could spend all day arguing this point). In fact it can be argued that the only reason that some (presumably rather arrogant) male-dominated tribes didn’t just have done with women as a gender is purely down to sex- partly because it allowed them to father children but mostly, obviously, because they really enjoyed it. Thus the availability of sex was historically not a woman’s most valuable asset to her male peers, but since it was something that men couldn’t/would rather not sort out between themselves it took on a great degree of value. It could even be argued that women have been ‘selling’ sex in exchange for being allowed to exist since the earliest origins of a male-dominated tribe structure, although you’d have to check with an actual anthropologist to clarify that point.

Since those early days of human history, prostitution has always remained one of those things that was always there, sort of tucked into the background and that never made most history books. However, that’s  not to say it has not affected history- the availability of pleasures of the flesh has kept more than one king away from his duties and sent his country into some degree of turmoil, and even Pope Alexander VI (a la, among other things, Assassin’s Creed II) once famously hired 50 prostitutes for a party known as the Ballet of the Chestnuts, where their clothes were auctioned off before both courtesans and guests (including several clergymen) crawled naked over the floor to first pick up chestnuts, and later compete to see who could have the most sex. In fact, for large swathes of history, prostitution was considered a relatively popular profession among lowborn women, whose only other choices were generally the church (if you could afford to get in), agriculture (which involved backbreaking toil, malnourishment and a generally poor quality of life), or serving work if you were lucky. It was relatively well-paid, required no real skill, was more exciting than most other walks of life and far less risky than a life of crime. Even nowadays sex workers are held with a degree of respect in many countries (such as The Netherlands and New Zealand) as being people stuck in a difficult situation who really don’t need the law trying to screw over (if you’ll pardon the pun) what little they have.

However, that doesn’t mean, and never has done, that prostitution is just some harmless little sideshow that we should simply ignore. The annual death rate among female prostitutes in the USA is around 200 per 100,000, meaning that over a (say) 10 year career one in fifty are likely to be killed. Compare that to a rate of 118 per 100,000 for America’s supposedly most dangerous profession, being a lumberjack. Added to this is the fact that prostitutes, many of whom are illegal immigrants, runaways or imported slaves, are rarely missed or even noticed by society, so make easy victims for predators and serial killers. Prostitution is often seen as a major contributory factor in the continued spread of STD’s such as HIV/AIDS, and is often targeted by women’s rights groups as being both degrading to women both directly involved and indirectly associated as well as slowing the decline of chauvinist attitudes. Then there is sex tourism (aka travelling to somewhere like Thailand to hire prostitutes because at home people might see you coming out), which is rapidly becoming one of the most distasteful, as well as dangerous & counter-productive, aspects of 21st century tourism. And then, of course, there is sex trafficking, perhaps the lowest of the low as far as all human activities go. Sex trafficking is the practice of abducting young women to sell into slavery as prostitutes, both within a country and across international borders, which would be morally repugnant enough if it wasn’t for the fact that a significant proportion of those trafficked are children, sometimes sold even by their own families. Around three-quarters of human trafficking today, the largest slavery operation in the history of the world, is concerned with the global sex trade, and is the fastest growing criminal activity on the planet. Much of it is connected to other aspects of organised crime, such as the drugs wars in Mexico, and can therefore be directly linked to large-scale theft, murder and smuggling, amongst other crimes. In India & Bangaladesh, some 40% of prostitutes are thought to be children, many of whom use a highly addictive drug linked to diabetes and high blood pressure to make them seem older & fatter (research suggests that men find fuller physiques more attractive when under stress or hardship). Looking through some of these figures & reading some of the stories surrounding them, it’s hard not to be struck by how low humanity has the potential to stoop when it ceases to think or care.

Over the last 100 or so years, as life has got less hard for the average woman and job opportunities have expanded, prevailing attitudes towards, and the prevalence & amount of, prostitution have declined heavily, and it is now frequently seen more as a rather distasteful sideshow to modern living that most would rather avoid. But to contrast against this we have the fact that the industry is both very much alive across the world, but could even be said to be thriving- the ‘labour’ of slave prostitutes is worth tens of billions of dollars worldwide. The trouble is, because it is an inherently seedy sideshow, it is impossible to get rid of, with legislation usually causing it to merely go underground and leading to further degradation in living conditions and welfare of sex workers, and regulating it is similarly tricky. Thus, it’s very hard for governments to know what to do about an industry that they recognise will always be there but is immensely prone to crime, human rights abuse and health issues. Unless the world, in a rather unlikely twist learns to live largely without prostitutes, a black stain is unfortunately likely to remain on our pride and dignity as a race. Exactly how this should be dealt with is still a little unclear.