Well, he's definitely got at least Flap 1 set because you can see the slats extended. I cannot recall if Flap 1 is a takeoff flap setting for the 737 but, if it is not, they would have got a config warning on applying thrust. My quarterbacking would guess at wrong weights in the FMC (ZFW entered into the GWT field etc) giving the wrong speeds on the speed tape. I'm very glad the PF did the right thing when confronted with a lack of lift and gave the wings a few more drops of IAS before having another go when a bigger arrow of upward energy was formed. He didn't panic and try and stop, so I reckon he made a good job out of a bad situation, even if they did (maybe) cause that problem in the first place. Incorrect FMC entries have been around for quite some time now and I'm sure there will be more but let's hope better data entry procedures will mitigate against too many occurring.