"This Jam has met its Match"
lol, the voice did it for me, excellent! Did you record yourself and process it through something? Very entertaining at any rate. I like the little boxing glove cursor, great little aesthetic touch! I like the fighter names, it seemed to me like they fit with a physical and mental anatomy and science vibe. I would play this game with updates. There is nearly an endless amount of things you can add to make this more engaging than it already is, that makes those things hard to list, which I feel you already know.
Some considerations:
Screenshake when you take damage for the sense of getting hit, to go with the screen flash and on hit sfx.
Visual Effects on the cards when they are matched or mismatched. Like I could see cards popping up with a scaling effect and a particle of some kind that trails behind them as they land into the defeated pile. Also maybe even a glow effect or particles of some kind that run on the cards as and when you select them, then the "SelectionEffect" stops running after the cards have been checked for their match.
Normally, I would not have chosen on my own to play such a game, just not my style. Since you have minimal objects and UI, adding visual feedback on those elements would be a major focus to push the game further! Matching UI Elements to fit your overall theme and some engaging music and you have a nicely polished memory matching game! With some updates and more fights, I would come back to play again!
I was able to complete a round taking 1 hit of damage. I would even consider a step further for a challenge for players~ to add a 5th row or column (in higher level fights), or even swap cards positions (while visualizing the fact) every so often to throw the player off so not only do they need to memorize all the static positions, but if someone's memory is vivid, now they have to remember where they seen certain cards swap to on the grid and keep track of those changes.
<3