The blood, oh the blood!
The graphics are based on live-action models, which lends the characters smooth and lifelike animations. Each fighter also had a personalized voice that was also recorded from an actual human. So the game looked and sounded real.
The AI was tricky at first, but eventually one can find a pattern. I once saw a guy beat the entire game at an arcade by just doing the flying kick from Liu Kang, and it wasn't set on easy either. I could beat the game just by following a sweep-freeze-uppercut combo with SZ. So not much I in the AI. 2 player mode was much more fun, as usual, because then you can learn to execute and defend against the best combos and techniques. As an opportunist (in this and every fighting game), I played an vindictive defensive game that worked well.
Gameplay was very intuitive, at least to me. low and high punches and kicks, and that's it. 4 attack buttons, that's it. Up and down, back and forward plus a button or more would execute various special punches (uppercut, backhand, nutshot) and kicks (sweeps, roundhouse, axe). In addition, the standard Street Fighter style commands (down forward down stuff) executed special moves. This was the first game where I experienced directional tapping for special moves (Scorpion's spear). Very nice.
Despite some of the crappier iterations put out by the MK crew, this game will always be special to me for the easy and fun gameplay. And dangling spines.