hey, new player here.
being an ui geek i just couldnt resist doing some modding right off the bat.
the player frame was the first thing i removed, this just completely broke immersion for me. what purpose does it actually serve?
i also modded the frames on enemies/npc, only keeping the top left corner.
as suggested in this thread, putting the health bar on top of enemies would make them a lot easier too see.
if you placed the health bar on top you could "ornament" it with the tactial frame, combining the two. here is a crude screenshot to illustrate my point:

you could also make objects obscuring enemies somewhat transparant to also aid visibility.
while i think this roguelike has one of the better interfaces ive seen i still think there's plenty room for improvement. will post a separate thread on ui feedback once i've put more hours into the game..