Gyarados needs to consistently do 110 with preferrably flash bites instead of belts. While facing Luxchomp speed you often have to focus on being faster and not always getting rescue energy or seeker, and early power sprays really hurt you. Roserade Gl can cause problems too where you are too much behind to catch up. Vilegar with rescue energy just destroys you. All they have to do is take out regice so poltergiest knocks you out and combee only lasts so long under trainer lock. But if teched and played properly it can be a good deck. But definitely not unbeatable at all.