i had the most fun with this demo of all of entries, this reminds me of ziggurat. the little details add up and there's charm everywhere, the sound and visuals are great. some negatives: the jump height is frustratingly low, the areas feel a little too cramped, if the arenas were twice as large as they are now that would be more fun i think. a few of the enemy types have too much health for how easy they are to fight. some of the enemies have very long pauses between attacks and movements. maybe increase their attack speed, movement speed, and attack frequency but decrease their health. i would also suggest changing the itch icon to be a screenshot of the game, or something to indicate its an FPS, as i almost skipped over this one thinking it was a genre i don't care for.
overall its a great start and i like these kinds of FPS's and this is a good example of the genre.