I think it was a matter of everybody (and I mean the vets and the kids) knocking the rust off and getting into synch.
The talk about how Allen gets "pushed back" is way overblown. Watch ANY NFL Center handle a good NT one and one, and you'll see him get "pushed back". What matters is not getting bowled over or run around. Rather it is slowing down the NT and retaining control of him for maybe 3 seconds.
I'm going to rewatch the game and pay close attention to Noteboom and Allen. But as I watched the game live, they looked just fine. That was one heck of a noteworthy, very good, veteran D line they were playing against. They're not going to play against much better.
Especially since there are 2 new starters, the kids, the Oline ought to get better as the year progresses.