To understand why the current city center looks so different, we can view the damage map of the city center (thanks to "Hengelo toen & nu"). This was drawn up in July of 1945 and indicates the extent of damage to the various buildings.

Red means "destroyed", green means "severely damaged" and yellow means "slightly damaged". Usually all red and green buildings will have disappeared from the scene.
Schadekaart hengelo
The bombing of Hengelo was carried out by the Allies on 6 and 7 October 1944. The main purpose was the rail connection, because the Germans transported war material via this route. It was certainly not a precision bombing and large parts of the city center were hit.
The photo below clearly shows how Molenstraat and Stationsplein have actually completely disappeared. A reconstruction plan had to be drawn up for this.
If you want to know more about this period and the further history of Hengelo, take a look at Museum Hengelo.
Hengelo na het bombardement