After an in-depth look at Erik Karlsson in Sweden's 3-1 victory over Slovakia, I'm optimistic. He was poised all night, and had a wicked shot: He scored a power-play goal on a very strong snap shot that went top corner. He also assisted on the game-winning goal, had five shots on net, and was +1 overall.
About his game: He fills the role of powerplay quarterback very well. He's got good vision in the offensive end, and was often the only Swede on the point while the other four pressured the Slovaks on the powerplay. He has good foot speed, and is agile enough to avoid hits more often than not. I would have to say that Karlsson had more poise than Victor Hedman, his defensive partner, who is expected to be in competition for the first-overall pick this year. There is a knock on Karlsson, and that's his size: 5'11", 168 lbs. There were two times that come to mind where it was an issue (neither resulted in a good scoring chance, though), but his speed usually makes up for what he lacks in size. And the other positive note is that size is something that you can--and he will--improve.
Andre Petersson was alright, but didn't really stand out. He took a roughing penalty, and had one shot on the night. His line was not the Swede's best one.
The final Sens prospect in the tournament, Jim O'Brien, played his second game of the tournament for USA, a 4-3 win. He had no points, four shots, and was even.
As for the Hedman watch, he wasn't quite what I expected. The scouting report that I'd heard was he was big like Zdeno Chara, and as poised as Nicklas Lidstrom (although maybe not quite to the same extent of either). Overall, though, he looked a lot more like Chara than Lidstrom, more of a hulking physical presence (he's 6'6" and 220 lbs) than an intimidating offensive threat. Hedman was far less impressive than Karlsson, but his size and his speed were very appealing; he may have simply been trying to do too much on the night.
Finally, John Tavares: He "only" had four points (2G, 2A) in a 15-0 win over Kazakhstan, and was +2 with nine shots. But he's only second in tournament scoring, with seven points in two games: Teammate Cody Hodgson has eight points in the tourney so far.