1. What changed for the Patriots' offense in the third quarter? There were two things that stood out from their opening drive (5 plays, 78 yards, in just 2:19). They went empty on the first play with two receivers, one tight end, one fullback and one running back, spreading out the Texans' base defense. That simplified the picture for quarterback Tom Brady in terms of what the Texans were doing defensively (Danny Amendola for 16 yards was easy pickings with linebacker Darryl Sharpton in coverage). Then, on the next three plays, they tilted the field by aligning multiple receivers to one side while attacking the opposite side in the passing game with either tight end Rob Gronkowski or running back Shane Vereen. This, from our viewpoint, allowed them to exploit the Texans' linebackers and safeties in coverage with two of their best players -- Gronkowski and Vereen.
2. That theme continued on the next drive. There were multiple empty formations out of two-back sets to exploit the Texans' base defense and make them cover the width of the field. Then, on Vereen's 9-yard touchdown catch, the Patriots tilted the field to the right side with receiver Julian Edelman, tight end Matthew Mulligan and Amendola, and brought Gronkowski up the seam off the left side of the line on the "open" side of the field. That drew significant attention from the Texans' defense in the end zone (3 players), leaving Vereen unaccounted for in the left flat for the catch and easy walk-in for the score.
3. Those looked like two of the Patriots' main halftime adjustments -- empty formations out of two-back sets and creating more of an "open" side of the field and attacking it.
4. I counted seven Texans that made contact with fullback James Develin on Develin's 1-yard touchdown run. Best effort play I've seen this year.
5. Defensively, one thing that stood out from the first play of the Texans' initial drive was a switch to more man coverage. Cornerbacks were aligned closer to the line of scrimmage than they were in the first half and played more physical against receivers. It wasn't all man (e.g. Andre Johnson for 28 yards with 8:00 remaining) but it seemed to be more of it than the first half.
6. Bill Belichick called an uncharacteristic early-in-the-half timeout when the Texans' offense faced a third-and-1 with 12 minutes remaining in the quarter. The Patriots had sent in their short-yardage defense, with linebackers Dane Fletcher and Jamie Collins replacing defensive backs Logan Ryan and Duron Harmon, but there was one problem -- the Texans had a three-receiver set on the field. Perhaps sensing they were vulnerable to the big play with just two players in the secondary, Belichick must have felt it was important to get the right personnel on the field. But after the timeout, the Texans went with a two-receiver package, and so the Patriots countered in their base 3-4 and defensive end Joe Vellano made an excellent play to drive right tackle Derek Newton into the backfield and stop Ben Tate for no gain to force the punt. That was one of the "game within the game" type situations.
7. Random observation: Chandler Jones might have had a quieter day rushing the passer than some of his previous outings, but he crashed down multiple times to either take on blocks or race past them and was one of the team's best run defenders in the game (e.g. 4:50 remaining in third quarter).
8. On Case Keenum's 5-yard quarterback-keeper TD run, it looked like the Patriots beat themselves before the snap by not aligning wide enough on the defensive right side with either linebacker Collins and/or cornerbacks Aqib Talib and Kyle Arrington all inside the two receivers who were aligned tight to the formation (Johnson, Keshawn Martin). That allowed Johnson and Martin to block down on Arrington and Collins, and when Talib took an initial step inside at the snap, there was no one to set the edge. Nice play by the Texans, but one we'd guess that Belichick will feel could have been played better.