Mortal Kombat 1 is a video game realesed by Midway Entertainment in 1992. The game was famous for the brutal fatality moves and amount of gore and blood, that previous titles never showed before. The game series was one of the ones most crucial for the formation of the ESRB rating system.
Main Story :
The main premise of the game is that you are one of seven combatants to participate in a tournament of mortal Kombat, or that is what is believed, secretly the sorcerer Shang Tsung is manipulating the tournament in his favor with the help of the Half Dragon Goro, who killed the last champion, The Great Kung Lao 500 years ago. Only seven kombatants survive and each combatant must fight each other in a series of battles before they face the four armed Goro, and then Shang Tsung himself. In the end only Lui Khang survived and managed to supposedly kill Goro and beat Shang Tsung returning the kombat back to its rightful owner the Shaolin Monks.
Canon Story :
Like any fighting game the story end depends on the fighter you choose, but ultimately they contribute to the main ending story of the game.
Scorpions ending :
If you play and win as Scorpion then you will receive the message that talks about how Scorpian was killed by Sub-zero and he returned as the revenant to kill Sub-zero in the story which he ultimately does and he must live with the knowledge that he is a revenant. This is confirmed as canon as Bi-Han does die in Mortal Kombat 1 and Scorpion is still a revenant in MK 2.
Lui Khangs ending :
If you play and win as Lui Khang then you will receive the message that talks about how you beat Shang Tsung and returned the kombat back to the hands of the rightful owners. This is the only actual proper ending to the game as MK 2 opens with Lui Khang's story.
Non-Canon story :
This is the story of the kombatants that doesn't contribute to the main storyline of the game.
If you play and win as Raiden you will see the message about how the earth realm kombatants and Shang Tsung and Goro were too easy for Raiden and he brought the end of the world. This is non-canon as not only does it contradict Raiden but the world is intact in MK2.