The original, somewhat more logical, better looking, and cheaper Armageddon!
Story-wise, it sums up Shao Khan's attempts at a Earthrealm takeover from MK II, MK III, and UMK III, this is his last chance at it. If you watch the intro, you'll get a 5-minute history lesson. And for where the series is at, it makes some sense for this game to happen.
Of course the main draw is the roster, they pack EVERY character introduced to this point, all 32 of them, even the unselectable boss characters. All those beatings Khan gave you in previous versions, you can take it out on the AI with hammer in hand. Exclusive to the PS1 release, you can also be the "old" versions of Kung Lao, Rayden, Jax, and Kano, a forgotten precursor to Hyper Street Fighter II on SF: Anniversary Collection.
Returning is the combo system, I don't like it or use it, but if I had this and the 3D games to choose, I'd shut up and learn it. Each character (maybe not the bosses) also gets a full allotment of Fatalities, Friendships, Babalities, and Animalities (show Mercy first). Also, you can a wide range of stages to fight at, stretching all the games. Though having not played MK3 or Ultimate before this, I was disappointed in the Pit 3 (I love Pit II).
This series was on the decline when this came out and this breath a little life into it. It's nostalgic for the gamers that grew up on the series. I rate this as the second best MK game behind MK II and to what came afterward, this is the last gasp of greatness. Besides, the $10 you spend here is worth more than the $10 you may find Armageddon for, trust me : )