they heard terrible growing howls roaring sound outside
A wolf can howl at the moon. A plane's engine roars.

and saw planes approaching from the east west


They looked exactly like the planes they’d seen all these days so they knew those weren’t Soviet planes.
From how you described the day before they saw some Heinkels like these:


And now you must be speaking of Stukas like these:


circling up and down towards the ground in a couple of miles from the village
You can't circle up and down. A plane usually takes a wide loop after the attack to take another pass.

The aim target of the bombers was hidden behind the thick woods bounding encircling the village
When the bombers left were finally gone, everyone saw columns of thick black smoke rising above the trees
They saw the smoke only now? Not during the attack?

the smell of burnt out explosives with thick notes tinges of oily smoke that was rising from a few trucks seized with engulfed with fire
‘Civilians!’ Peter whispered feeling a desperate furry fury rising up from deep inside. ‘They destroyed the kill civilians!’
Who were these people, where were they going? Did anyone of the villagers knew this? Did anyone tried to guess anything about it?

If they were the refugees they should be fleeing away from the front (to the East). Here a logic inconsistency: if they were fleeing East then their village was situated to the West of the place our protagonist was at the moment. This way they should have passed Shumovka on their way. If their village was located to the East of Shumovka then the attack couldn't have taken place so near.

Out of a corner of an eye In the corner of his vision he noticed other villagers do the same
still pale from the shock
with a bleeding limp instead stump in the place of her right leg
He tore off his belt
How can you tear off your belt? unbuckled, unfastened

on the limp slightly above
limp is a verb:
limp intransitive verb \ˈlimp\
: to walk in a slow and awkward way because of an injury to a leg or foot
: to go or continue slowly or with difficulty

limb maybe?

to stop the bleeding
When they came back to the village
Oh my, what did they do to the wounded? Did they bury the dead?

nothing could save them from being torn apart by the explosive explosions or buried alive under the rubble of the houses
The villagers could managed to save some of the victims of the aerial attack, including that woman he helped
This should be said earlier

some of the villagers volunteered to look after them nurse
Some of the victims looked really terrible; they were limping, bleeding and groaning
Peter was astonished at the words of Ann that these were not considered severely damaged. He imagined a picture of a really severe wound and shuddered in disgust horror.
dis·gust noun \di-ˈskəst, dis-ˈgəst also diz-\ (Отвращение)
: a strong feeling of dislike for something that has a very unpleasant appearance, taste, smell, etc.
: annoyance and anger that you feel toward something because it is not good, fair, appropriate, etc.

What I don't understand is - Peter saw them all. How could he miss the heavily wounded?

Later, when they were sitting in silence in Ann’s house, unable to even look at the food, let alone much less eating it Peter asked:
‘on the other hand, they could not overlook confuse the women and children with soldiers.
Actually they could. All the piliot sees is the truck and some people inside.

‘Do you think when the ground forces troops will behave differently from what we've seen today ?’