Shortly after starting nearly everything faded to black, giving just a small glimpse of the dangers ahead. Without that initial glimpse, I'd have had no clue what was there to deal with and likely would have stopped sooner out of frustration. After that, only a very tiny area around the character was visible. I lost a bunch, until I started to tap the right arrow to move very slowly forward, looking for an edge or the start of spikes, and jumping over them. Eventually I got to a ledge beyond the area I had glimpsed. I jumped and hit a wall. I tried to jump off it, but did not see anything to land on, and instead started to fall. At this point I was going down, but could not see what was a safe path down, and what was an endless drop. I jumped, holding right, and kept tapping jump to climb any walls I found, though mostly ended up continuing downward. I used this method to get through to the point where I saw 2 large bubbles with text, one saying something about gaining an air jump, but I seem to have paid too much attention to it as I then fell down a hole and had to restart.
I'm not really a fan of the gameplay. The area of light around the character is far too small. It feels like you have to inch your way through slowly, and then rely on luck, and repeated tries, memorizing the dangers you can't see. If there is a way to enlarge the light, or other mechanic to get through other than what I did, then I missed it. Personally, I'd like a larger radius of light, even if it was an ability, or had limits, such as a power meter that you use up. Another option could be a flashlight that you can point around you (maybe with the mouse). It can still be short range, but enough to give the player some clue as to what is ahead.
The music is overall decent for the game, except for the part where it beeps like you are getting closer to danger. When you are in the dark, having something audible to warn you of danger like that could be useful, and with little visual to work with, sound becomes more important. I would use a different track without that approaching danger warning sound.