- Yes, it’s a quarrel and it’s traditionally enveloped in plasma energy after it has been launched from a Wookiee bowcaster and it causes serious amounts of damage on impact.
- It was established that she knew how to defend herself with a staff. We don’t know if that was the only melee weapon she knows how to use. We don’t know her past- that was a big theme of the movie. In any case it was still more fighting experience than Luke had when he first had to use a light saber against enemies.
- Kylo Ren in top fighting condition would have beaten her easily. Fortunately for her Kylo Ren had been hit by the plasma energy enveloped quarrel a few minutes earlier. He was using all of his will power to keep himself upright and fighting. He still soundly beat Finn, but by the time Rey fought him he was tired and still grievously injured and honestly likely not completely in the right mindset to allow the Force to work effectively through him thanks to him killing his dad moments before. He would need to either be completely clear of mind or give in to his rage to use the full power of the light or dark side- he is definitely not clear of mind and given his earlier struggles it is likely that guilt and sorrow are lessening the impact of his rage.
- Kylo Ren does not want to kill Rey. Why? I have no idea, hopefully we will find out more. He offers to teach her. He seems incredibly interested when he finds out that there is a girl with Finn and the droid. He knows something. Throughout the fight, even though he is seriously injured and not completely centered on his rage he is holding back when he fights her.
- She gives in to the force completely. She wins, but it isn’t a one sided, easy victory. Kylo Ren is a very formidable opponent even weakened as he was.
Honestly when they fight him the next time they will be in serious trouble unless Luke fights alongside them. But given all the handicaps he had it is realistic in the context of Star Wars that she won that battle.