You absolutely nailed the "crystal" aspect of the enemies, and it's incredibly fun to break them. The controls work really well, and I like that you have to decide between recharging your flashlight and moving/fighting. The game is pretty fun, and the music/sounds are pretty solid.
The only thing that bothered me a bit, if I may share a bit of feedback, was a lack of visual clarity. I know this seems weird to comment as the game is supposed to be dark, but something about the contrast, or maybe the brightness of the lights, gave me a weird sense of not understanding the background and foreground elements very well. When I was fighting an enemy this wasn't an issue, but exploring the cave was super claustrophobic to me, like the scenario was bending around itself. I believe this was intentional, but I think it was a bit too much (for me).
Despite of that, the visuals really represent the theme of the game, and the atmosphere is fantastic. It's incredibly fun to fight enemies, and as I said the flashlight mechanic works very well. Great job!
Oh, now that I'm reading some of the comments, I see that you talked about lights not being rendered properly for some people. Maybe this was the case for me, it would explain a lot! Do you know if this may be caused by my browser?