u/Awesome_FriendlyKid

I also like to imagine the character select would be done via a personality quiz, with questions like
How will you celebrate your first TKO victory?
A. A tall stack of pancakes for lunch and a long nap.
B. By sharing a dance with the nicest lady in the crowd.
C. Immediately begin training for my second, and third!

And after a few questions, you get shown the character that the game thinks suits you most... And, alternatively, then you get the option to see who else you can pick.

1. Gabby Jay - it's Gabby Jay.
2. Bear Hugger - you can't intercept his taunts at the beginning, so it's a bit slower, but it's nothing I can't handle.
3. Piston Hurricane - surprisingly hard without gut punches - not only can you not intercept his Hurricane Rush, but also his low hooks or uppercuts, and he surprisingly throws quite a few of them.
4. Bald Bull - he's this low purely because after his second knockdown, he keeps doing Bull Charges until either he or you go down. Not good.

5. Bob Charlie - like Piston, after his first knockdown, he becomes an absolute nuisance with his "Shuck and Jive" phase and me not being able to intercept any of his low hooks or uppercuts.
6. Dragon Chan - even without being able to get him dizzy, his jabs are pretty easy to intercept if you just know when they're coming.
7. Masked Muscle - one of the four fights with a designated 'hit with a jab for an instant knockdown' move (his headbutt), making him pretty easy. Even then, though, once again, you can't effectively intercept his hooks and uppercuts. Also, don't get cocky and try to counter his spit attack.
8. Mr. Sandman - I was really surprised to find out that Sandman was one of the relatively easier fights. Even then, though, you should watch out for his uppercuts, since you can't intercept them.

9. Aran Ryan - I learned the hard way that Aran's clinch can't be stopped with a jab - you can ONLY counter it with a body blow. Even then, how easy he is to get a dizzy knockdown on made that basically irrelevant.
10. Heike Kagero - my biggest surprise with Heike is that getting him dizzy is not only possible, but also pretty easy. That being said, though, you can't intercept his comeback hook or his uppercuts, so he was pretty hard to figure out after his first knockdown.
11. Mad Clown - another fighter who can be hit with a jab at the right time for an instant knockdown (his earclap after his juggling), plus unlike Bear Hugger, he doesn't do his taunt that much and you don't have to rely on it for quick damage.
12. Super Macho Man - like Dragon and Muscle, you can't get a dizzy knockdown on him without many body blows. Also quite a few of his moves can't be intercepted with jabs, if at all. On my playthrough, he decided to do three Exercise Program As in a row, which just about made me want to pick him up and suplex him through the ring.

13. Narcis Prince - for a guy who insists that you're not gonna hit his face, Narcis sure has some very easy to intercept jabs. That being said, yeah, that's basically your only hope. I recommend waiting for his three jab combo, blocking the first two and then countering the third to make him angry. Alternatively, wait for his left jab-right jab combo, block the first one and then intercept the other. After that, you're basically home free.
14. Hoy Quarlow - another character with a 'hit a jab for an instant knockdown' attack with his cane lunges. They are fast, but counterable. His Open Palm and Spinfist can also be countered with a right jab if your timing is good, so use that to your advantage. Just be careful about when you punch him, because getting shoved is pain.
15. Rick Bruiser - I was NOT expecting THIS to be the hardest fight, but as I found out, Rick actually has very few moves that a jab can hit - whether it be intercepting OR dodging and countering. As such, here is the strategy I found for beating Rick:
-First, do the usual dizzy knockdown strategy by throwing one unstunned jab, dodging his counter-punch and intercepting his first two jabs, but instead of intercepting his hook, dodge out of the way, throw two alternating jabs and then a super uppercut.
-After he gets up, throw another super uppercut and hope he takes it to the face, then dodge his counter-punch. After that, dodge his hook, jab him to stun him and throw another uppercut to put him down a second time.
-Block and dodge his three-part combo, throw another unstunned jab, dodge his counterpunch, intercept his first jab and then throw one final super uppercut. I guess Nick must have been doing the same challenge as me, because I only managed to eek out a win when Rick decided to let me.
16. Nick Bruiser - The only thing more embarrassing than Rick being the hardest fight in the run is that Nick then turned out to be the EASIEST. I even accidentally hit a frame-perfect counter-punch on his first jab for a hypothetical tied world record... But you know I had to wait for him to do his dive punch so that I can intercept it for the TKO. Okay, listen, I had just spent 15 minutes trying to get past Rick, I needed something to make myself feel better.