The twin boosters touching down within seconds were impressive. I wonder how closely they were flying on the way back? They separated at about 7000 kph, burned down to zero then back up to some fairly good velocity to get back in just a few minutes. At separation they were just a few meters apart, and at touchdown their landing sites look to be a few hundred meters apart. As far as I know, they are GPS and maybe inertial guidance - no radar or laser range finders to fly in formation. Due to fuel constraints they'd both want to take a fairly direct route back. It'd be interesting to know their offset distance and velocity...
Too bad about the central core. Apparently they fire 3 of the 9 engines to slow for re-entry but in this case only 1 ignited. Even with a longer burn (?) apparently it came down at about 300 mph at impact. Once they saw there was a problem with the engines, I wonder if they intentionally guided it away from the drone ship. No sense punching a hole in it...