I've only seen games between USA, Canada, and Russia so these are the only teams I will comment on.
Nitchuskin has been dominant, and remember he's only 17 years old and playing with 3rd line Russian players. I see shades of Malkin in him every game, been following him for 6 months now and he's gonna be a special player, IMO he should be in the conversation for first overall.
Mike Reilly for the US has shown some nice progress, he reminds me of a young Mike Green.
Oulette for Canada has been exceptional as advertised, really smart player.
Galchenyuk has really impressed me, he has that rare ability to completely hide his intentions. Such a lethal combination of size and skill, and then there's that shot... he's gonna be a steal at #3 overall.
Trouba has really increased his stock in my books. He's a lot smarter than I once thought with better hockey IQ. Exceptional skater, reminds me of a better skating Kronwall.
Kucherov has stood out in every game I've seen. Great skater, pro shot, possesses that knack of finding open space, and he has a great motor.
John Gibson has been a rock. Sooo mentally strong, understated athleticism, big frame, excellent technical ability to read the play. Such a beauty.
Vasilevaki has elite #1 potential. So much raw talent and athleticism, huge frame, perfect at predicting the play, never quits on a play. Professional demeanour, can't believe he slid to TB.