I played the game a bit, went up to the Centauer (300 HPs) but killing it won't open the door on the same floor I think. The Phantasy Star dungeon presentation works great, I like the monster animations and the music. The gameplay loop is addictive and the game felt well balanced.
In my opinion the game could benefit from shortcuts to town, for example every 2 boss fights, after the third one I stopped getting back to town yet not getting to spend my money was still a bit unsatisfying. I think both while walking and during fights mashing the buttons might also skip the current animation, there are plenty of moments where you want it to go faster, as fast as you press buttons.
I'm curious since you made such a game for this Jam, are you going to participate in the Dungeon Crawler Jam as well?