Something I noticed after a second viewing.
Not sure if it has been mentioned yet, I am sure it has, but I believe Kylo Ren's mask is key to explaining how some scenes unfolded the way they did, negating some often heard criticism.
Kylo's mask is a powerful Sith Artifact, no doubt. It allows Kylo Ren to focus his hatred, and greatly increase his force power. The other Knights of Ren are using similar masks to increase their potential with the dark side.
But Kylo's training in the dark side of the force is not complete. His main issue is his self confidence / self image. He fears being weak. The mask serves the added purpose of hiding his former self, and making him appear strong (well it does also make him strong literally).
When Kylo takes off his mask for the first time during his interrogation of Rey, he wants to prove to himself he is strong and confident, even without the mask. Previous scenes with Snork and the First Order Commander left him frustrated and vulnerable. As a result, he wants to prove he does not need help (=the mask) to be strong, so takes off the mask.
But when he tries to intimidate/manipulate Rey without the mask, this quickly backfires. Rey exposes Kylo's fears, which causes him to panic and quickly retreat to seek the advice from Snork.
Some criticism has been that Rey's Force powers develop too quickly. I actually think Kylo's injury in addition to his lack of mask made him very weak. Weak enough for Rey to beat him. Not Rey miraculously becoming all powerful without training.
During the Han Solo / Kylo Ren face-off. through taking off his mask a second time, Kylo wishes to face his doubts and perceived weakness. When Kylo says he is unsure if he can do it, I think he actually means killing his father and fully embracing the dark side. He might have some conflicted feelings, but if he is to redeem himself, he has to kill his father. The last rays of sunlight disappearing in the background symbolizes Kylo's definite turn to the dark side.
