Not bad, but not great
I know your thoughts on it (judging from the description), so I probably won't say anything that hasn't already occured to you.
I do, however, have to commend you for your vocal recording skills. I still haven't gotten that perfected yet. The problem in this song doesn't lie in the vocals, but in the music.
The composition's not thorough, and the guitars are nowhere near as loud and forefront as they should be. Furthermore, FL Slayer is the worst fucking VSTi ever for guitars (although I'm sure other people know worse ones).
So, twas a noble effort, but at least you recognized that it's not exactly the best work you've done.