Glass Joe

If you need help with this guy, then you are in bad shape.  There are some strategies to really whoop his ass.  For the main part, dodge his hits and then keep hitting him in the face (this works for almost everybody. It is called counter punching).  When he goes up and taunts and then comes down, hit him in the stomach and you might KO him (if you hit him quick enough).  Glass Joe likes to get up on the 1 count and whenever somebody gets up on the one count, just hit him with one star-uppercut and he is down on the mat.

Von Kaiser

He is a little harder.  What you do at first is wait until 40 seconds during the match and try to hit him without him attempting a hit so you can get a star.  Then after he attemps a hit, counter hit him to stun him and give him an uppercut.  This will automatically knock him on the mat.  Another thing you can do is, after his big uppercut, keep jump-punching him left, right, left, right, until he gets knocked down again.

Piston Honda

Mainly, wait until he punches and then keep counter-punching.  He will try to do a piston charge (his special move).  He goes up, goes to the left, goes to the right, goes back to the center, and he will come after you.  Right when he comes down, hit him in the stomach.  If you don't do it right, then keep blocking his hits (by pressing down). Also, if you don't knock him down by hitting him in the stomach, just block his first hit and hit him in the face a few times and block his next hit and hit him in the face again until you do it five times (max).

Don Flamenco

He will not attempt to hit you unless you hit him first.  Hit him and then dodge his groovy uppercut.  Then keep hitting him in the face with a left/right/left/right combination.  If you keep alternating high left and right hits, he will stay stunned until he is knocked on the mat.  If you knock him down twice before 39 seconds, you will most likely get a KO on him. Another thing you can do is after you knock him down and he gets up, right away keep hitting him with left stomach punches to get stars from him.

King Hippo

The only way that you can hit him is to wait until he does a strong punch (the punch where he lifts his arm up and opens his mouth).  Hit him in the mouth and then hit him in the stomach eight times (nine times if you are fast enough).  If you are not too sure of when he is going to do his strong punch, hold UP on the directional pad before he punches. If he is going to do his strong punch, he will pause with his mouth open for about a second longer and it will give you a better chance of hitting him in his mouth. Anyways, keep doing this and you will knock him down.  One knockdown for him will be an automatic KO.

Great Tiger

For the first minute, hit him in the head. He will block it and then he will try to hit you.  Block that hit and then you can counter hit him 5 times in the head.  Then just keep repeating this until the first minute of the round is over.  Then he will duck to the left and uppercut and then he will duck to the right and uppercut.  When he ducks left, do a low left punch to get a star.  When he ducks right, do a low right punch to get a star.  After some of his uppercuts, hit him in the face after he attemps to uppercut you and then give him an uppercut.
About 2:30 in the match, he will get up and do his mysterious tiger punch.  He will teleport around the room and hit you.  Just press down to block for five of his hits (try to time them right) and he will be stunned.  Then hit him in the head with a punch.
Back to the first minute of the first round. If you can time it right, you can wait until the diamond on his head flashes (this is what he does before he punches you). Hit him right when the diamond starts flashing to get a star off of him.

Bald Bull

Here is a good way to knock him down quickly.  When the match begins, hit him twice in the face, then give him an uppercut.  Then hit him in the face once, and then give him another uppercut.  Then him him in the face again, and then give him an uppercut.  Keep doing this until he gets knocked down to the mat.  During the normal fight, he will do two swing punches in a row.  After that, he will do a swing punch and a lot of big uppercuts, or he will do 3 normal punches.  Uppercutting him when he is stunned is sometimes difficult.  About 2 minutes in the match, he will do his "Bull Charge".  He goes up to the top of the ring and then he will hop down three times and give you a knockdown uppercut.  Right after the third jump, hit him in the stomach (it has to be timed right) and he will be knocked down.

Piston Honda 2

This is Piston Honda's rematch.  He is harder to hit and he is a lot faster.  He is still pretty easy to defeat.  This time, when he does his infamous Piston punch, he will jump to the center and then he will jump back down and do his punch.  If you get him in the stomach right when he comes down, you will get an automatic KO on him.  Besides Glass Joe, he is the only other guy that you can KO with one hit.

Soda Popinski

Soda Popinski is harder and faster.  He will mainly do 2 swing punches in a row or 2 big uppercuts in a row; and sometimes he will throw in a quick unexpected jab.  Sometimes, he will just do three jabs in a row. 
If you try to block one of his big ducking uppercuts, he will be stunned and crouched down and you can hit him in the stomach to get a star.  Then after you get a star, wait until he does another big uppercut. Dodge it and counter-punch hin in the face (with the speed boost, not normally) and uppercut him. If you are not speed-punching, he can usually dodge your uppercut, so be careful.

Bald Bull 2

This Bald Bull is a little harder.  You cannot sneak punches on him unless he punches you first.  He is also the only character who can get up on the nine count.  Also, besides the bull charge, you have to use one of your power uppercuts to knock him down.  When you see bald bull keep changing his guard up and down for no apparent reason, just hit him in anywhere and you will get a free star.  He is tougher in this one.  Just get his energy all the way down and then give him an uppercut. 
Oh yeah, if you dodge his first "bull charge", then he will go up again, but this time, he will jump up two spaces instead of four.  Hit him in the stomach after he jumps down two times.  This shorter bull charge is easier to counter than the longer bull charge.

Don Flamenco 2

This second Don Flamenco is harder than the first one.  He will do hits like this and he will do swing hits until 1:30 in the round.  Don't be a dumbass like me and try to sneak in punches to get stars.  Just dodge his punches and then hit him after he punches.  When 1:30 comes, he will do his old fashioned "hit me and I will swing back" routine.  Sometimes, you will hit him and he won't swing back, so your hearts can run out a lot.  After 1:30 in the second round, he will then start to do his jab and swing punches on you.  There isn't any real tricks or strategies to him, you just got to watch out for some of his punches and try to TKO him.

Mr. Sandman

This guy is pretty hard.  For the first minute or more, he will do quick punches that are kinda hard to dodge.  Just try to avoid them and keep counter-hitting him after he punches.  After that, he will do swing punches.  To counter his swing punches, you hit him in the face once, and then you keep hitting him in the stomach a whole spermful of times. The best thing to do is to punch at his head so he can dodge it and retaliate with a swing punch, and then counter his swing punch. If he doesn't retaliate with a punch and just blocks your hit, that means that he is about to do his Dream Punch.  Be ready to avoid his Dream Punch.  He will keep moving fast in one place and the moment he pauses, dodge to the left three times and hopefully you can avoid his Sandman punch.  Then hit him in the face and keep hitting him in the stomach.  During the second or third round, he will keep doing Dream Punches, so you have to learn how to dodge them sooner or later.

One of the hardest tricks in the game (you can't EVEN do it on NESticle... unless you have the fast-mac version of the rom) is to get stars off of Mr. Sandman. You can only do this with the actual game cartridge and the actual system. In the third round, you have to hit Mr. Sandman in the stomach (he will block it and try to hit you back) and hit him in the face before he tries to hit you back. I can barely do it. I didn't even know you could do it until RedTom told me. You can do this in the first two rounds, but it won't give you a star. Credit goes to RedTom for this trick.

Super Macho Man

This guy is very fast and strong.  He will do swing punches and big uppercuts for most of the time.  If you lose all of your hearts, he can do a funky kind of big uppercut.  When he starts moving fast in one place, he is ready to do a weak Macho Spin.  Just get ready to dodge it.  After you dodge it, you can hit him in the head a few times.  If you knock him down and he gets back up, he will always do his strong Macho Spin.  He will pull back for the spin and he can spin 3 to 14 times in a row (it depends).  Just keep dodging as much as you can.  Oh yeah, when he pauses before he does a weak Macho Spin, hold your guard up for a second and then drop your guard and hit him in the stomach (you will usually get a star by doing this).  That is the only way to hit him in the stomach.

Mike Tyson is the final boss of Mike Tyson's punch-out.  After Mike Tyson got arrested, Mr. Dream became the boss of Nintendo's re-release.  Both Mike Tyson and Mr. Dream's moves and strategies are the same on both games.

For the first 1:30, he will do nothing but quick big uppercuts that will knock you down with one hit.  Try your best to keep dodging these punches and you can get 2 punches on him after he tries to hit you with a big uppercut.  Also when you counter-attack, counter-attack him on the same side that he swings at you to take more energy away.  The only way that these punches will not knock you down in one hit is if you have full energy and you try to block it.  After 1:30, he will then do swing jabs for the rest of the time.  These will not knock you down on one hit (thankfully) but are a little harder to dodge at first. 
At the beginning of the second round, he will do eight or ten lightning quick jabs (it sometimes depends on the hearts you start out with in the second round).  Just quickly block them and hit him in the stomach to get stars.  After that, he will do swing jabs and big uppercuts.  This time, the big uppercuts will not knock you down automatically and you can get more hits out of him when you counter-attack.  After 1:30 in the match, both of his eyes will keep blinking.  Hit him in the face or the stomach and get ready to block all of his punches (four of them, if you block them succesfully).  He just does a lot of swing punches, kind of like the "Piston Punch".  A thing you can do is to block his first punch, and then counter-punch him four times, and repeat for the other four punches.
For round three, his kinds of hits (jab, uppercut, swing) will be more random and hard to guess.  If he pauses for a while, and then does a big uppercut, and pauses again, you will know that he is going to do two lightning-quick jabs, so be prepared and either dodge or block (don't duck).  Just try to survive and hopefully, you can TKO Mike Tyson! (or Mr. Dream, whatever comes first).

Master Phred

This guy is the hardest character in the galaxy.  So far, nobody has found a strategy that works on him.  If you hit him, consider yourself the luckiest person on the planet Earth.  Master Phred is unstoppable and he cannot be defeated no matter what.  Just kidding (again), we all know that Master Phred sucks.
If you have Phred's Cool Punch-Out, then Master Phred's strategies are the same as Piston Honda's.  E-mail me if you want to find out how to download this cool rom hack.