Mr Zelenskyy's latest video statement came on Sunday evening after Russian forces increased their shelling across Ukraine and efforts to evacuate 200,000 people from the besieged city of Mariupol were blocked for a second day in a row.
In the town of Irpin, on the northwest outskirts of the capital Kyiv, about eight civilians - including four members of one family - were killed when missiles struck, according to the local mayor.
Mr Zelenskyy said: "We will not forgive the destroyed houses. We will not forgive the missile that our air defence shot down over Okhmatdyt today. And more than five hundred other such missiles that hit our land in Ukraine, our people, our children.
"We will not forgive the shooting of unarmed people. Destruction of our infrastructure. We will not forgive. Hundreds and hundreds of victims. Thousands and thousands suffering. And God will not forgive. Not today. Not tomorrow. Never. And instead of forgiveness, there will be a day of judgement."
He added: "We heard promises that there will be humanitarian corridors. They are not here. Instead of humanitarian corridors, they can only make bloody ones.
"Today a family was killed in Irpin. Man, woman and two children. Right on the road. As in a shooting gallery. When they tried to just get out of the city, to be saved."
The civilian death toll from hostilities across Ukraine since Russia launched its invasion on 24 February stands at 364, including more than 20 children, the United Nations said on Sunday.
And more than 1.5 million Ukrainians have streamed out of the country in just 11 days in what the UN is now calling Europe's fastest-moving refugee crisis since the end of World War Two.
President Zelenskyy also heaped criticism on Western leaders for not responding to an announcement by Russia's defence ministry that it would strike Ukraine's defence enterprises on Monday.
In a statement on Sunday evening carried by Russian state news agency Tass, defence ministry spokesman Igor Konashenkov said: "We urge all personnel of Ukrainian defence industry plants... to leave the territory of their enterprises."
In response, Mr Zelenskyy said: "I didn't hear even a single world leader react to this. The audacity of the aggressor is a clear signal to the West that the sanctions imposed on Russia are not sufficient.
"Thousands of people work there. Hundreds of thousands live nearby. This is murder. Conscious murder."
Meanwhile, Russian President Vladimir Putin told Turkish President Tayyip Erdogan in a phone call on Sunday that Russia would only halt its military operation if Ukraine stopped fighting and Moscow's demands were met, according to the Kremlin.
The Kremlin also said Mr Putin was ready for dialogue to end the fighting but that any attempt to draw out talks would fail.