I quit at the 5th level but had a lot of fun on the 4 others. I actually didn't mind the steep difficulty curve, I just naturally got better at each level by trying (and dying) over and over again. Since each level has very different layout and requires different "flashlight" strategies, that process kind of had to be repeated each time (even if I did get better overall), so I'm not sure having easier levels would really help for the harder ones (but I might be wrong). Mostly I felt like your game difficulty was "fair", I could always see where and why I made a mistake, so I always had this urge to try "just one more time"... until I passed the level. But it's definitely not for all players and requires some patience.
I also really liked the flashlight mechanic, it struck a good balance between reactivity and strategy, so it never felt like I just had to "get good", I could also try a slightly different strategy to get through levels.
Art and music are simplistic but fit well. Besides I was so focused on the flashlight and the enemies that I pretty much turned everything else off...
My only complaint would be that I didn't really feel like it fits the theme, but that's not super important.
Overall: simple but very clever idea, really great execution, had tons of fun, really great work!