There seem to be three types of review on there.
1. Hur hur, rubbish. 1 star (There are seriously reviews like that)
2. This isn't Lord of the Rings. 1 star
3. I really loved how they took that piece from the Silmarillion and explored the concept. 5 star
The people giving it low ratings don't appear to know the source materials. Disclaimer - I have not yet seen it so I am witholding judgement, but the reviews are embarrassing.