Ok with the power of hindsight my comment below is funny because I got walled at what was the last level LOL
My main thought is still that it is much too dark, which is a shame because I do really like the core mechanic! My main issue though (besides that I would've loved more levels) is that the mechanics are generally inconsistently applied. In the first room, the bat enemies chase you when you flash, but in the rest of the game they simply go about their business. In the second level, you have walls you can dash through in the light (really cool idea!) but is absent in the last level, which doesn't really telegraph its solution to you in any way. I'm also just completely unsure what the skull does.
There's a lot of great ideas in play here, and I do honestly mean a lot. The visuals are all around good and I don't think they need any tinkering. Given even a little more time in the oven, I can see it coming together really well! As of now though I just don't think the execution is there. Would love to play a longer version if you ever want to make one!