According to the video's information:
EMB-721 Sertanejo heavy and insane takeoff in Carlos Prates
"EMB-721 Sertanejo heavy and insane takeoff in Carlos Prates.
Full fuel, 6 on board plus luggage
Copilot was 0 hours, crystallized and kept pulling the youke [sic]. Cpt took over, lowered his nose and managed to fly."
Basically, the inexperienced pilot miscalculated or misread the takeoff speed, and lifted too early, too hard.
Then when the plane just wallowed, he kept pulling back thinking that the laws of physics would make an exception for him if he kept on insisting hard enough. The captain was yelling: “Leave it to me. Stop pulling the yoke!”. The captain took over control, lowered the nose just a bit to allow airspeed to build up, and then gained altitude.
P.S.: One does wonder about the wisdom of giving a pilot with zero hours on the plane, the role as takeoff pilot from that airport in those conditions.
Heavy plane, crosswind takeoff, utterly unforgiving runway runoff (the runway runoff is a cliff leading to densely populated urban area, including condos!), and multiple passengers, including screaming kids.