I caught the replay of the US-Swiss game on the Swiss federation's YouTube page and it was definitely terrible performance from the US team; they were a shadow of the team that was so dominant at the U17 WHC last month.
The biggest issues were definitely on the defensive side, as the coverage and decision making was quite poor. I noticed it at the U17 WHC to a degree, but Emery is a real liability defensively, and I think he was primarily responsible for the first two Swiss goals. Cole Hutson has talent for sure, but he takes some major risks on the powerplay, and got burned by it once here on the Swiss shorthanded goal. Goaltending certainly wasn't where it needed to be either.
Eiserman was pretty invisible, and seems to be on a major cold streak since the U17 WHC; not sure if he's been playing well and just snakebit in the USHL, but he wasn't good here and it was telling that he and Hagens got split up part way through the game. I thought Hagens also had a very poor showing despite the goal. I'm still not entirely sure what to make of the forward group beyond that as of yet; Humphrey's seems to be the best of the next tier but I'm not sure where his ceiling is as a prospect. Perhaps a few others will emerge more consistently over the coarse of the year or take a big development jump next year.
Credit to the Swiss for playing a strong team game and working hard to shut the US offense down while making the most of all their scoring chances. I expect the US team to perform much better once the tournament play starts but they definitely laid an egg in this one.