They're putting in a new system. From what I gather the WR routes are more dependant on the positioning of the defender than in the past (TE routes may be less so). The QB and WR have to be on the same page for this to work. Vandenberg has a history of being tentative on the road, and WR's are for the most part young. Davis the only real experienced WR has yet to prove he can be the go to man. Pass blocking left a great deal to be desired. NIU had a decent pass rush and kept them coming all day. Throw in the fact the field conditions at Soldier Field are awful, the weather wasn't cooperative either. The bright spot in this is they didn't make any fatal mistakes with the passing game, no turnovers.
How much of this they can clean up between week 1 and week 2 is a good question. I expect the pass blocking to get cleaned up a lot, especially by the front five. Pass blocking for HB, FB, and TE will probably be more of a work in progress. The young WR's may come along slowly.
So much of this is a head game for Vandenberg that it is hard to say how well he will do in week two. He has a history of doing well at home, but this is a new offense. Unfortunately, Vandenberg seems to be a bit of a fair weather QB so pray for favorable weather.