It's only my point of view : If this art was a real wot battle ... you can see after 3 second a ammo of a arty ... get out from the sky ... AND EXPLODE ON THE IS-3 Yes ... cause in world of tank every tank with the track destroyed die by arty ! WoT logic ! But damn fucking nice job !
They try to fire onto the turret since the Russians have a different theory of ammunition storage, so they store their ammo in the turret. Therefore if the fired an AP or an HE at the turret it would send the turret flying off the tank in some cases. The fire would do little if the hatch was shut, besides leave scorch marks. If it was an incendiary round it would have blown it up.
Unless I'm mistaken those are only external fuel tanks. Fuel isn't "explosive" so long as you don't pressurize the ignition. It's just set a large fire and eventually burn out. If a small non incendiary bullet hit the tank it wouldn't even light.
With AP, no. Its just basically a big bullet. Its possible with HE, but that would just be a small supplement to the actual explosion from the shell. This would probably destroyed the whole gas tank, and the one next to it. It looks like the tank was empty and an anti tank or AP round went through it.