For the most part, just fight your way through like you normally would. Sometimes the AI will just feel like kicking your ass and you won't get a single hit off them. That's just the way this game works. After a few attempts, you will move onto the next fight. There's not many tips I can actually give as I suck at this game and just got through each fight eventually after failing a bunch of times.
I recommend using a wired controller as you'll be able to follow my guide a little easier. If not, you probably can figure out what I'm talking about by using the keyboard.
NOTE: Do not ever back out of the game, to check any guides or anything at all. You will be reset back to Fight 1. I did this after being stuck on Goro and well let's just say I was pissed.
Some fighting moves (actually the only ones I ever used) are
Alternate between both punches (
) as fast as you can. You can quickly knock a good chunk of health off the AI doing this but don't do it forever, they will eventually catch on to what you're doing and stop you.
Instead, quickly stop what you're doing while your opponent is confused. Hold down (
) then follow with a punch. (
) This will send the AI flying in the air.
The other important move is the jump kick. This will be very useful. Jump away from the AI until you two are on both sides of the screen. (
) then jump towards the opponent and kick them as soon as you're close enough to land the kick but before touching the ground. (
When playing as Sub-Zero (The Blue Guy for idiots like me that don't know), there is also a freeze that is useful if you get used to it. Start by pressing down (
) then immediately press in the direction of your opponent. (
) which will freeze them. Then quickly follow by a jump kick.
Once you finish fighting 1 vs 1 you will have to fight 1 vs 2. Yes, you're the one against two AI unfortunately. You will have to defeat both AI with 1 health bar and do this for both rounds. It's unfair and a bit difficult. I'd recommend switching up characters after losing and see what works best for you.
After struggling with the 1 vs 1 and definitely the 1 vs 2 (Unless you're good of course), you will have to fight two bosses.
The First Boss - GORO
This in my opinion is the hardest fight in all of Mortal Kombat 1, but I found a very cheep way to beat him and only took a few hits from his throw attack.
Play as Sub-Zero for the next two fights.
Once you're a good distance away from him, jump kick him. Once he's down, immediately jump kick again. Then jump away from him. Before he can get up, already be throwing a freeze at him. Once he's frozen, repeat with 2 more jump kicks and a freeze until he's defeated. It's quite simple once you get the freeze attack down. It's hard to get used to but it's a very good way of fighting him. You will probably get hit with a few of his throw attacks as you're trying to freeze him. This is annoying, but if you are able to land 2 jump kicks on him, then you should eventually manage to defeat him. 1 jump kick never worked. Make sure to do the 2nd jump kick immediately after the first one, so Goro is still on the ground while you're doing your 2nd jump kick. You will knock him down as he's getting up.
The Second Boss - Forgot the name because wasn't important
This isn't too bad, but it's definitely luck based.
Play as Sub-Zero or any character actually. I was just playing as Sub-Zero so why not recommend it. I got this on my 4th attempt.
Immediately be holding jump towards the boss. If you jump away, you will get hit with the throw attack. If you're immediately jumping towards the boss, it will back away. Once he's stuck on the wall, land 2 jump kicks. Back away and just keep jump kicking.
The only thing I did on the boss was jump kick, and jump away. Eventually I beat it.