The features of a game are very important. Why else would they be listed on the back of the box?
If you didn’t know the list of features a particular game offered why would you buy it? Because of the box artwork? Perhaps. But the discerning game player will want a fairly comprehensive understanding of the title before they fork out their hard earned cash. Unfortunately, most games aren't that radically different from each other. That’s because every few years there are innovations that push collective development in a new direction.
Rival development studios see these new concepts and subtly put them to work in their own titles, or simply copy them outright. How many times have you seen 'bullet time' since Max Payne? Or delivered a finishing move in an fighting title looked suspiciously like a fatality from Mortal Kombat?
1) The cover system
Games have used cover for years. Even back in the Doom days you still had to pop out from behind a wall to take a few pot shots now and then. You could go as far as to say that Mario using a block to stop a turtle dragon's fireballs was some form of a cover system. Metal Gear Solid hinted at the concept by allowing you to stick to walls and peak around corners, however Killswitch was the first modern shooter to use a proper cover system where you could actually stick to cover and blind fire.
It wasn’t until Gears of War that the true potential of the cover system as a great game mechanic would be realised. This "Stop and Pop" gameplay changed the pace of the traditional shooter, as instead of just running and gunning, the player had to think more tactically. Flanking became more important than it ever was before, and consequently we’ve had a range of games with cover systems ever since.
Some have been flat out copies, such as 50 Cent: Blood in the Sand, and others such as Killzone 2 have pushed this further with a stick to cover system. Then there is Rainbow 6: Vegas, Metal Gear Solid 4, Resident Evil 5 - it seems that without a cover system, it's now actually difficult for anyone to market a game as an action title.
The cover system is probably going to be around for quite some time simply because it makes sense. It adds a sense of realism to games and makes shooters more strategic, often improving the pacing and tension of each encounter. The days of running and gunning are far from over, but the more methodical, tactical shooter has started to dominate and we owe this evolution to the cover system.
2) The moral dilemma
I’ll admit I don’t actually know the first game where good or bad choices had to be made by the player but I do remember the first game where it was a major feature and made other developers take notice.
Star Wars: Knights Of the Old Republic is to this day still not only one of the best Star Wars games ever made, but also one of the best role playing games, period. The combat, graphics, settlings, and story - all of this had such incredible polish that it practically made BioWare a household name.
One of the standout features of the title was being able to either follow the "light side" or the "dark side". This was done by having the player make moral decisions. While Knights Of the Old Republic was fairly straightforward with good and evil choices, future games to use this concept would elaborate further. Knights Of the Old Republic 2 had additional grey area in its choices, so the decisions were tougher to make. Mass Effect didn’t even give you the choices between good or evil, as you were always going to be the guy saving the galaxy. Your choices were more confined to playing things by the books, or punching panicking scientists in the face.
Fable II also took its morals system further than the first one by giving you choices with real consequences beyond merely the reactions of others. In order to be a good guy, you actually had to make sacrifices.
Adding a set of moral choices into a game does a similar thing to adding a cover system. It adds a sense of realism. It also provides a way of making you care about the game. If you have to make decisions that will impact your character and the world around them, that’s something you will want to put some thought into.
Traditionally, moralistic choices have been featured in role-playing games, however other genres are now trying to incorporate this concept with varying success. Even the brutally violent Grand Theft Auto IV gave you moments where you could choose to be compassionate. It seems certain that as we go forward developers will find more interesting ways of implementing choices that really make you think, and aren’t always entirely black and white.
3) Achievements and Trophies
A single, unified achievement system has made a world of difference in console gaming. It makes perfect sense - if you want to keep gamers occupied and prepared to thrash your title until the small hours, you'll need a robust vehicle to deliver encouragement. There's nothing quite as addictive as chasing particular goals that provide instant gratification in the form of additional points to pad out your online profile.
Even awful games gain a measure of replayability if they can offer these small bursts of adrenaline cunningly disguised as rewards, so it's little wonder that developers now have to include them if they want a hope of getting their console titles published. It wasn't that long ago that gaming success was only ever measured by an in-game leaderboard. If you were lucky, it saved itself so you didn't lose it each time you rebooted your gaming device. Now, unless a dozen of your close friends can witness your triumph online it barely seems worth playing the game at all.
This single innovation has picked up where massively multiplayer games like Everquest and World of Warcraft left off. It provides that "just one more round" intravenous drip lacking in the majority of budget titles published prior to its inception, and for that reason alone, achievements and trophies are here to stay.