That was some interesting insight! The system is partially turn based. Enemies won't attack when choosing actions or selecting items, but depending on their "movement" rate they might be able to perform their actions first or multiple times, that's why it seems you get so many extra hits from them. Everytime you get a new relic (like the mirror), your health and energy goes up a bit but so does your character movement, even if this is not apparent, so it becomes much less of a problem later on, when enemies are harder but slower. I believe the enemies you mention are probably the fastest in the game, so I might tweak that a bit if it feels unfair. I tried to simplify the battle system as much as I could for the purposes of the game jam, but hopefully it will work at the end.
I'm really thankful your opinion! Getting the balance right is always an issue of mine!