His brilliance is masked on limited viewing because he's got a slightly awkward style and is very one-footed when dribbling.
His sprint capacity and movement are elite; he has a nose for space and the timing of his runs are exceptional. His finishing is extremely good, potentially elite; he has great composure in the box, and the inside of his left foot is more reliable than anyone not named Lionel Messi. If he can improve his weaker foot, he'll be unstoppbale in front of goal. He also has a very good appreciation of runners, especially in counter-attack situations; the weight and timing of his passing is surprisingly good. Also a very good ball carrier in transition; box-to-box in the blink of an eye.
My reading of him, and where I think a coach at a top club will have to work with him, is his ability to play against teams camped in their own defensive third. The patience, the practiced patterns, tight-knit control and accurate passing that's needed; he hasn't faced these things before, and I think it will take him a while to work it out and become effective in these situstions. But he has the ball control, intelligence and skill to do it, and he'll be certified world class when he does.