According to the Genji Gamepedia page, Reflect's ability is:
With lightning-quick swipes of his sword, Genji reflects an oncoming projectile and sends it rebounding towards his opponent.
It's not exactly clear what this means. Does this mean that reflect can only reflect non-hitscan projectiles? Or can he also deflect hitscan projectiles such as S76's Pulse Rifle bullets or Widowmaker's shots? Can he also reflect Ultimates such as Roadhog's Whole Hog or Hanzo's Dragonstrike?