Difficulty Spike: In single-player mode, the difficulty ramps up quite suddenly on the 4th stage (the Pit) after the first "Test Your Might" Mini-Game. This is probably to showcase the Pit's stage fatality to novices since the AI tends to favour an uppercut finisher much more.
Fan Nickname: Sweat Fighter for the infamous SNES port, which censors most of the fatalities and changes all of the blood into sweat.
Game-Breaker: If an expert Sonya player manages to land a single Leg Grab, consider yourself already dead.
The game introduced juggling to fighting games, a game mechanic later improved by other franchises such as Tekken. Basically, if a player knocks their opponent into the air, they can keep attacking them. It had Game-Breaker potential, so combo breaking measures were put in place in later games not only of the series, but also of other franchises.
The game also popularized simplified move commands, more exactly buttonless motions (such as ← ← →) and simplified motion+buttons (← → 👊 ). These commands would later become standard for specialized command moves.
In the Genesis port, if you achieved the conditions to fight Reptile during an endurance match, you will fight two Reptiles, and the second one will look like a buggy version of another, non-ninja fighter, most often Sonya.
Sub-Zero has an infinite against Goro (and only Goro), making the latter easy if you can get the timing down.
When Reptile was first introduced, characters such as Scorpion and Liu Kang were unable to challenge him thanks to a design oversight: the player couldn't block during the previous match and had to finish it with a Fatality but some Fatality inputs required the block button. In the Genesis and Sega CD ports, however, the inputs for Scorpion and Kang do work and properly summon Reptile if set right before the character lands from a jump. Since the characters can't block in the air, the game lets it slide. Unfortunately, this does not work for Sonya because she has block as the last input for her Fatality and it ends up registered by the game as such when she lands.
Narm: Johnny Cage's "knocked down" sprite just makes it look like he got shoved over, especially with how his head is held up off the ground, as if he's looking up at his opponent in a daze. This is extra funny if you've just uppercutted him into the Pit.
The game's biggest draw, its Fatalities. The seven playable characters have only one Finishing Move, plus one Stage Fatality that anyone can perform. The only ones that are remotely shocking by today's standards are Sub-Zero's decapitation with dangling spine, Kano's heart rip, and the aforementioned stage Fatality, where you fall down onto a pit of spikes. The others are either a bog-standard decapitation (now considered the most mundane way to kill someone in a video game), immolation (which the T-rated Mortal Kombat vs. DC Universe got away with reusing), and Liu Kang's cartwheel kick, which is also bloodless and may not even truly kill the victim. With later games, as well as competitors, increasing both the variety and brutality of the finishers, it can be hard to get excited for MK1's Fatalities, but back in the day, they were truly shocking, to the point where they're part of the reason why the Entertainment Software Rating Board was created.
A character example with Goro. At the time, Goro was so well known because he was so different from the playable fighters, and his design and difficulty made him truly unique among video game bosses. Now, a fighting game having a larger than life boss/sub-boss is the standard. As for his difficulty, there's a reason why SNK Boss is a trope.
One-Scene Wonder: This game makes an actual anime appearance in High Score Girl where the series' protagonists are talking about this game.
A subversion; under most circumstances the Genesis version would have been considered the bad port due to its looser controls and noticeably inferior graphics and sound, while the SNES port was very close to the arcade version. However, players were all too happy to overlook the problems of the Genesis version for one very simple reason: it had the blood and gore intact, while the SNES version replaced it with sweat, and replaced the decapitation Fatalities, not to mention that the SNES version had much laggier controls.
The Game Boy version is a straight example, featuring horrendous slowdown (There's nearly a full second of lag between you pressing a button and your fighter carrying out the corresponding action, and you must take this delay into account while playing) and poor black and white renderings of the original sprites. The sequel, thankfully, is much better.
At first glance, the port for the Sega CD seems fine, with all the content of the Genesis version (complete with blood and gore unlocked from the start) and better music thanks to the system's CD capabilities. Unfortunately, the game suffers from terrible load times, doesn't have anything new to make up for being released months after the other versions, and worst of all when you start the game you have to sit through all two minutes of the infamous "Mortal Monday" commercial (advertising the very game you're already playing) with no way to skip it. And to top it off, while the CD format allowed them to use the actual arcade music as red book audio, a coding error causes the music tracks to play on the wrong stages.
The Amiga version (which was released only in Europe) is based off the Genesis version, but removes all background animation and is designed around a one-button joystick because of the Amiga's continued use of that outdated controller. A two-button joystick is usable, but doesn't really address the fact that it doesn't play anything like the arcade.
Spiritual Adaptation: Allegedly, it was originally going to be a game based off Bloodsport, but, like with Doom and Alien, Donkey Kong and Popeye, and so on, it became it's own thing, and spawned an award winning franchise.
That One Boss: Goro, who is often regarded as being harder than Shang Tsung since all his moves do so much more damage than anyone else's (apart from Shang Tsung's flaming skull, which are easy to see coming because of the screaming sound).
Vindicated by History: While Sub-Zero and Raiden's SNES Fatalities were accused of They Changed It, Now It Sucks! just for not being the original arcade Fatalities, they eventually gained fans for being better showcases of those characters' ice and electricity powers respectively, and still being gruesome ways to die. The concepts behind these Fatalities would be revisited as early as Mortal Kombat II, a game which was obviously not Bowdlerized on consoles.
What Do You Mean, It's for Kids?: During an interview with Ed Boon, a reporter comments on the amount of violence and blood, and how a game like that could never be possibly meant for kids, to which Ed Boon responds "Actually, it is."
