In various threads, I have brought up the run game. Dallas was supposed to be a power running team that its passing game fed off of. That really hasn't happened at all. It has, however, happened in San Francisco. SF hits you first with McCaffrey and sometimes Samuel, gets your defense on its heels and Purdy is competent enough to take advantage. SF didn't get that going today, lost Samuel in the 1st quarter and McCaffrey in the 3rd.
I will say this, Dallas is a front running team. When things are good, they snowball. When things are bad . . . they snowball.
As a side note, the Browns have a really good defense playing at home on a cold, rainy day.