Saw the video.Seems to me like an engine surge,followed by another engine surge. Both of these could be due multiple bird bits(very common in rainy conditions and all the more dangerous since the pilot can never see them right untill the moment it is too late!). The bright explosive flash seen later on the video could well be either one of the damaged engines' blades disintegrating and either rupturing a fuel line or piercing a fuel tank(therby causing the explosion and the flash). The rest can be a little less imaginative. As it DID crash.
Alternatively,the 'flashes' were the aircraft strobes.
But it DID crash...
My 2 krunos...