Cool game, interesting idea that fits the theme well. Some feedback:
-The AI sometimes aims at enemies through walls. This could be fixed easily with a raycast check
-The enemy balancing feels a little off - I got the impression that the slimes were supposed to be the easiest enemies, but they felt significantly harder than the bats and the octopuses
-Consider adding some checkpoints. If the player dies near the end and is sent back to the very start of the game, they will probably just quit
-There should be a key to advance text boxes, rather than an on-screen button that has to be clicked. It's a little annoying when the rest of the game is played only with the keyboard, but you have to grab the mouse just to click through text boxes