This is a lovely story, your descriptions are vivid and I personally enjoyed it. I was looking for a book in the YW competition that deserved a vote and this one definitely does! Your cover drew me in but it was your writing that caught my attention. One thing, the flashbacks are slightly confusing although they do show the character's thoughts whirring through their mind. Maybe that was the desired effect? I did enjoy it though. Voted.
Sad! Poor Jeze! Poor Gabriel!
You wrote this really well. You have a good handle over spelling and grammar, although I did notice a few minor typos. The demon-angel thing has been done before, it's true, but you seemed to make it your own. You're definitely quite the talent :)