When you think of fighting games, what's the first thing that comes to mind? For me, I think of Street Fighter II, and Mortal Kombat. While Street Fighter changed the world with the "fireball" dynamic, I think that Mortal Kombat deserves some credit for a few other changes to the game...some you might not even have known (no, not Mortal Kombat Mythologies: Sub Zero. That game sucked).
Let's have a look at the three most influential games:
#1. Mortal Kombat (Arcade, Genesis, SNES, 1992)
The series starts off my differentiating itself from any other game of its time. The first thing that people (especially Joe Lieberman) notice is the absurd quantities of blood that flow from every character. Every hit in this game drains the equivalent of 2 gallons of blood. The ability to do "fatalities," which essentially turned your opponent into a dismembered heap, were also well recieved.
Aside from the gore, though, MKI had a lot going for it. The "block" button was an interesting change from those of us that were used to holding "back" to block. That requitered some good dexterity to stay alive. The game used real actors, unlike the animated SFII, and looked much better than most games out there. Likewise, the special moves for each character were well thought out, and relatively well balanced (although I still think that Sub-Zero's freeze blast is the cheapest move to hit gaming).
The console releases of MKI were very close, but with one exception -- only the Genesis had blood. The Super Nintendo release could be Game Genied to turn the sweat red, but it just wasn't the same. In Mortal Kombat II, both console versions were given blood.
Speaking of MKII, it wasn't a huge leap over MKI. New characters, new moves, and an extra fatality for every character is hardly groundbreaking.
Mortal Kombat 3 (Arcade, Genesis, SNES, PC, Sega Saturn 1995)
Now we're getting somewhere. The third incarnation of the Mortal Kombat series tried to change the formula, and really succeeded. There were the expected changes (graphical boost, new moves, more characters, new bosses), and then there were the brilliant changes that defined the fighting genre. And I'm not talking about the "Animalities," a move that was likely introduced when Midway just couldn't think of any other ways to kill someone.
For one, MKIII introduced the run button. Running wasn't really all that common in fighting games. The idea of "dashing" had just started to form, but running the entire screen was pretty new. Needless to say, players that relied on defensive tactics were in for a surprise. However, this isn't the biggest change to hit the series. What is?
This is the first popularized game to feature a combo system. When you get in close and hammer on buttons, you actually have to think (only a little bit, though) as to which buttons to hammer on to inflict the most damage. This evolved into the same basic combo system that gets used in modern day fighters. Pay homage!
Mortal Kombat 4 (Arcade, PS1, N64, PC, 1997)
And this is where everything starts to go bad. Feeling pressure from successful 3D games of the time (Virtua Fighter, Tekken...etc), Mortal Kombat decided to venture into the third dimension. The result is that, well, it's the same damned game. The third dimension does almost nothing for the game. Rather, it seems to complicate things, especially when the computer can side-step attacks in an instant, and you can't figure out how.
Another noticeable change was the introduction of weapons. THESE GUYS SHOOT FIRE AND ICE OUT OF THEIR HANDS! What the hell do they need weapons for!? The weapons, while fun the first time around, actually complicated things from the "freeze you then uppercut you" gameplay that was needed to win.
MK 4 was the beginning of the end for the series, as future games have stayed in 3D, and not looked much better. While Mortal Kombat: Deadly Alliance did tinker with an interesting combo system, and Mortal Kombat: Armageddon looks fun, this is the game that pushed Midway in that direction to begin with.