I beat all 3 levels on my second try, but there was an enemy one tile away as I reached the exit of the final level. On my first try, I died before I even found my character on the screen because the enemy spawned very close to me. Once I understood the flow, I found the concept to be really great. There was a good amount of tension. Turning the lights on for a split second to quickly check my route to the bling before going dark again was a lot of fun. The visible "Ouch!" text when you run into a wall turned out to be my favorite feature. Once I discovered that, I could stay in the dark for longer because I'd use the ouch text as a signal to change direction.
For anyone else trying to run this that has been away from Java land for quite some time, like I have, here's what worked for me: java -jar fnbling-in-the-dark.jar