Okay, so I gave this another go before bed, and I get it now. Oh boy do I get it, this is probably one of my favourite gameplay loops of the jam so far. It's so, so good. You guys absolutely cooked with this one and, if you'll allow me to stretch the food metaphor a little bit here, proceeded to put the food in the damn HVAC system instead of on the table. I'm going to spell out exactly what changed for me from one playthrough to the next, both so the team can take it as feedback if they want, and so any confused player reading the comments like I did can understand how you're supposed to play.
This game is much slower and more methodical than it appears at first glance. Mashing attack and constantly dodge-leaning so you can get more hits in is useless, the correct way to play is to only dodge into attacks you can parry, only attack into attacks you can parry, and only dodge out of attacks you can't parry. This way you always avoid taking damage if you do it correctly, and always get to deal damage because once you activate Golden Hour (by hitting the coin that appears after a parry), you slow down time which lets you get a combo on the enemy. You get a feel for how much time slows down after a while, and getting the follow-up parry to avoid taking damage during your combo becomes second nature. Once you slow down your gameplay, you start only looking for parries and can focus much better on the enemy patterns (including some pretty mean counter-attacks, like the second boss' stab attack that is absolutely impossible to notice if you're focused on landing as many hits as possible) and begin improving at each boss to the point of being able to no-hit the first two bosses somewhat reliably. And when you're able to do it... that's the juice. Dodge, parry, dodge, coin, stagger, gun, repeat... I'd found it before but it didn't click because I was trying to fill in the dead air, those few moments where you need to be ready to parry immediately, with junk damage that was doing nothing to the boss, causing me to get hit, and making the game feel sluggish and unresponsive when it was a playstyle issue. The game does nothing to communicate this, you still look like you're making progress when you play it wrong, and until you play the game right, it feels like the game is wrong and not you.
And for the record, I think designing a game for yourself is a perfectly valid choice. I'm a firm believer in the idea that games are for everyone, but not every game is for everyone, and that both of those statements are equally important. The importance of good tutorialization and player onboarding is is a lesson I've learned myself after many game jams, and it isn't necessarily about making a game easier (though that may be the case), it's about giving players the tools they need to understand how the game works and to be able to engage with it on a level where they can enjoy what the creator has served.
Preferably on the table.