I really enjoyed your game! Usually people said that to me about my game, but here I understood why they said that, that the game opened up to them in a new way when they learned new mechanics.
At first I was just picking my offense and defense. After a while, I noticed that the things I choose (in which there is no word) turn out to be abilities in the upper left corner. And I have to choose attack or defense to activate them.
Initially I was just looking and didn't understand why the character was doing some extra action.
Oh, correction. Read it in the comments. Turns out fullscreen takes away the text display. However, for your game, you could call it a plus. I was able to navigate without text :D
So, I interrupted. Perhaps when doing an attack/defense, it would be worth doing some sort of glittering line fly through from left to right in the background of the skill. And if the skill is completely full, you could make that line bigger for the player to notice. You don't have to make the interface stay within its zone. These lines can cover the center of the screen a bit so that the player pays attention to it. However, this is just an example.
The gameplay is very addictive. With very little health, I made it through a few more floors on the shields only. Got to some floors with no background wall, just columns. Again, was without text, don't know which one is which :0
In general, you can seriously try to practice readability of the game with the erasure of the entire text from the game :D
The game is very interesting, addictive strongly.