Probably the main thing that stands out in the Celtics' play over the last 5-6 games since Bradley came back is that the defense has stepped up the intensity a notch, and they seem to be making many more defensive plays than they were earlier in the season.
Related to that is the other really noticeable change: the tempo. The Celtics are getting out in transition now, and it's turning into easy points. Usually these come off of defensive stops. The Celtics don't have an explosive offense, and they probably won't at any point this year. But they gain leads by going on big runs fueled by forced turnovers and quickly turning stops into easy buckets.
The bench at times has looked more impressive than the starters during this run in part because they seem to be much more willing and effective at pushing the tempo and getting out in transition like that.
Danny Ainge built the supporting cast this off-season to be effective at playing faster and getting in transition. Players like Terry, Lee, Green, and Barbosa all reflect the goal of playing this style. I think one of the keys to maintaining this success is going to be to continue pushing the tempo, and somehow getting the first unit guys in on that action.
Too often during this run the first unit guys have come out slow at the start of each half, and it's not until the quicker, higher energy bench guys get in that the Cs really take off. That's not going to work in the playoffs.
What the Celtics lacked through the first portion of this season was an identity. They didn't do anything that stood out compared to any other team. Playing quicker, forcing turnovers, blitzing the opponent's ballhandlers, and getting out in transition, while also playing grind-it-out half-court sets in high-pressure situations (the strength of the starting 5) can and should be this team's identity moving forward. They can go places with that.