Let's not kid ourselves, games today are for the most part, quite easy. Even those games that do provide genuine challenge tend to at the very least have an easy mode. In fact, one recently released, and critically acclaimed, game, New Super Mario Bros. Wii, actually had a "Play it for you" mode which, as you might imagine, played through the game for you if you got stuck.
So modern games do tend to be very accessible with either an easy difficulty curve, an easy difficulty setting, or just plain by being easy. Prince of Persia (the 2008 one) a game which I really loved (but I was in the minority) in fact wouldn't let you die. If you ever screwed up you were ported back to the last solid surface you stood on. Personally I thought that worked well in that game, but I must admit, it did tend to make thing a bit easier.
Why is this? Why is it that video games, a medium which once prided itself on being really difficult, are now made so that anyone can play them? Well, quite simply, games are not for the elite of the elite any more. The industry used to only make money by taking quarters from kids one at a time, and making things hard only made sense. The more time the player dies, the more money you get. As the home console became more popular however, the trend didn't seem to wane as quickly as one might expect. Indeed, there are brutally difficult games from the NES, SNES, and N64 era.
It wasn't until the 00's that the industry really started to notice that the old market of making games long and hard was really not as profitable as it used to be. Indeed, they found they could in fact make MORE money by making short, easy games, so gamers would move on very quickly from one $50 game to the next.
You see, game which are short and easy make many gamers (I don't want to throw out the term "casual gamers" here as that has a bad connotation to it.) happier than bashing their heads against a wall. For the most part (Single player games) this is FINE! If gamers want to spend $50 for a game that will last them 3 days on easy difficulty and then move on to the next shiny object, that's their choice.
However, there is a dark side to this. You see there is another subset of gamers, (Again, I don't want to throw out the term "hardcore" as this has bad connotations) who want challenge. Who revel in the idea of fighting an enormous monster, armed with nothing but a toothpick, and then, after countless deaths, to finally triumph against it, only to find that the next beast is even more difficult.
This leaves game developers with a difficult choice. (No pun intended.) Do they make more money from the ADD masses, or do they please the dedicated, loyal, yet much smaller, fanbase?
The answer many of them found is simple, difficulty settings. Include an "easy" setting for those who want to see the art assets and move on, and include more difficult settings for those who want a bigger challenge.
The problem with this is that not many people understand that there are three kinds of difficulty. Real difficulty, artificial difficulty, and fake difficulty.
Artificial difficulty is the most commonly used, and to be honest, the easiest form of difficulty to create. You see, artificial difficulty is when a game simply makes things harder to kill.
For example, in easy mode, perhaps the most common enemy has 10 health, and you do 5 damage per hit. Then in normal mode the most common enemy has 15 health and you do 4 damage per hit. Then finally, in hard mode, the same enemy has a whopping 20 health, and you do a mere 3 per hit. You see, things did just get a lot harder, as the same enemy which took only 2 hits to kill in easy mode now takes 7 hits to kill in hard mode.
So technically it is harder. Perhaps it also hits you harder as the difficulty scales up. Well that does make things harder, since now you die more quickly, and it dies less quickly, but it doesn't really require you to pay any more attention than you were before. While yes, it is "harder" and it will take longer to complete a game like this, there's nothing new to see. Star Wars: The Force Unleashed was like this. The harder difficulties were only "harder" because you died more quickly, and they died less quickly. The AI was no better. There were no new mechanics. Everything hit you harder, and you hit things less hard.
This is artificial difficulty.
Real difficulty is far more interesting than Artificial difficulty. You see, real difficulty means that something is actually hard. It requires pitch perfect execution to complete the tasks the game lays out for you. Super Meat Boy is a great example of this. You see, Super Meat Boy is probably the hardest game I've ever played. Not because of some difficulty slider, there is no difficulty slider in this game, there is only HARD. Not because things hit you hard, but because it simply requires pitch perfect execution. You have to perfectly jump between the obstacles in order to get to Bandage Girl and complete the levels.
Now, this game is not for everyone. Because it's HARD. Really HARD. That's ok though. Not everyone needs to be able to play the same games. That's why a lot of games are made, so that there's games for everyone.
When it comes to difficulty sliders, real difficulty actually adds new things for you to keep track of within the game. For example, Batman: Arkham Asylum's hardest difficulty, or Fallout: New Vegas's Hardcore setting.
Arkham Asylum (which is a fantastic game) had simple enough combat, you see. Square to punch, kick, hit, whatever, X to run (as always), Circle to stun your enemies... The fourth button, Triangle is where things get interesting. Counter. You see, on Easy and Normal difficulties, when an enemy was about to hit you, a blue flashing light would appear above their heads, and if you instantly hit triangle you would perform a powerful counterattack. The result was that, while I LOVED Arkham Asylum, you could, during most encounters (later in the game you encounter enemies with stun batons that can't be countered, and can only be dodged, and during most the game there are enemies with guns who will kill you if they so much as see you.) you can simply wait until you see a blue light, and then hit triangle to win. While this was far from the quickest way to victory, it would always win, if your reflexes were fast enough.
In hard difficulty though, while you still have counter, there's one vast difference. No indicator. The only way to know when to hit triangle is to keep an eye on each and every thug attacking you. A difficult task later in the game when you're fighting off ten or eleven guys. This provides real difficulty.
Fallout: New Vegas (Also a fantastic game) had perhaps an even better example of this. Anyone who's played Fallout 3 knows how Rads work. You have a small meter that shows how much radiation you've been exposed to, in addition to your standard health meter. It's a good mechanic. The more radiation you get the sicker you become, losing vital stats and such.
Fallout: New Vegas has an optional setting known as "Hardcore Mode" which, in addition to rads, added 3 more meters. Hunger, H20, and sleep. This was a brilliant example of real difficult giving you more meters to watch. Especially considering that in the Mojave Wasteland food, water, or a safe place to sleep can be hard to come by. In addition, all healing items went from being an instant heal, to healing you over time, keeping you from essentially injecting stimpack after stimpack to get past an especially tough group. Plus, crippled limbs could only be healed by a doctor, or one of two special (quite rare) items, "Hydras" or "Doctors Bags", or by a doctor. This, again, gives you more things to keep an eye on, not just increased damage and decreased health. Oh, and ammo has weight, meaning you can't just pick up all the ammo you find and sell it for thousands of caps, as I would in Fallout 3.
World of Warcraft has been experimenting with "Hard Mode" encounters over the past two years with Wrath of the Lich King and Cataclysm, which have optional "Hard Modes" in the raids which give superior loot. They've made both real and artificially difficult hard modes. For example, Flame Leviathan is, on normal mode, in Ulduar, a loot boss. I have literally never seen any group fail to kill him. He's stupidly easy.
On hard mode however, he adds four new mechanics, which make the fight MUCH more difficult. Beams of all sorts which you have to know to move out of and what each thing does. Adds spawn which must be killed... All sort of bad crap is on the floor you have to move out of... It's a much more interesting, and more difficult fight.
Hodir, however, is the opposite. There is literally not one new mechanic for his "Hard Mode". All you do is kill him, completely the same fight mechanics as normal, in fact you don't even do anything to trigger hard mode difficulty, in under 4 minutes. It's stupid.
Ah yes. Fake difficulty. Have you ever been playing a game, and seen what should be a simple enough task, only to have something completely unfair happen and stop you from achieving it?
For example, the old "one key, two doors, one door opens, the other breaks the key" puzzle that can be seen in places such as Braid. That is fake difficulty. There's no way for you to know which it is. No deduction, no fair way for you to succeed, other than through luck, or experience. (Failing first.)
That is fake difficulty. Fake difficulty is when something is hard, not because of ingenious mechanics, or even just by scaling things up... It's not hard because it requires perfect execution... It's hard because it requires MORE than perfect execution. It requires perfect execution and LUCK. Lots and lots of luck. Will the random energy beams the boss shoots hit me this time? Will the jump button choose to work, or fail this time? Why am I playing a game that's unfair?! These are all questions you will ask yourself which indicate fake difficulty.
Now understand this, Real Difficulty Vs. Artificial Difficulty is a real debate. Neither are, persay, bad. Both have their places. I'm not saying every game should add in tons of mechanics on hard modes, or that games should simply scale everything up. Personally, I like real difficulty being added to games more, but hey, that costs a lot more time and money to implement which could be better suited elsewhere in production.
Fake difficulty, however is BAD. BAD BAD BAD. You see, you can argue about things being as hard as you want them to be all you want, but they must always, ALWAYS be within reach of the player. If they aren't, there's no point in trying. Thus, Real and Artificial difficulty are both perfectly fine, but Fake difficulty is BAD.