I think it's pretty good for an early puzzle without time limit. definitely gives right feel for doing a puzzle in a dark place. far as I can see from the image it's quite dark, but doesn't seem like it's too dark to be able to complete.
as for everything else, don't over think it. it's usually when you stress yourself out over something like that, that there are generally mistakes. when I'm having difficulty with a post when Roleplaying with a friend, I find it's easier to settle and make progress when I take a moment to meditate on the scene, and the characters involved. closing your eyes for a moment and letting everything unfold in your mind, before trying to put it onto paper/word doc/etc. can be enlightening, and sometimes there's unexpected inspiration to be found. otherwise it might be good to get outside help; like if you have a writing buddy you enjoy working with, who will take on a role you're struggling with. reading through how someone else aproaches the same character might give new insight into your own approach.
I hope that helps a little! I'm glad things are going better now! just remember to take breaks, and enjoy yourself. ^_^