"We live in a violent, brutal dictatorship. Over the past 40 years it has gotten more and more violent and brutal," said Kah Walla, a civil society activist. "These 40 years are a huge setback for Cameroon."
Her support for Biya evaporated over the years as economic progress stalled, dissenting voices were silenced, and the oil-producing country of 27 million people became split by a separatist uprising that has killed thousands, and Boko Haram attacks in the north.
Biya has repeatedly defended his record in the past and says that the government has made strides to return peace to the minority English-speaking regions where separatists are trying to form their own state.
Millions still support Biya, although international observers have raised doubts about the fairness of elections that he routinely wins with ease. He spends long stretches in comfortable European hotels with his wife Chantal, frustrating many at home who believe the country's crises require closer attention.
Biya has ruled with openness and tolerance, said former minister Elvis Ngolle Ngolle. Old age, he said, has its advantages.
"The more you add up the age, the wiser you become – the more experienced, tolerant, logical you become," Ngolle said.
Popular journalist and whistleblower Paul Chouta disagrees. Chouta, an outspoken critic of Biya, has been repeatedly beaten and tortured in recent years. He lives in fear: just the sound of his floorboards creaking sends him into a panic.
On March 9 last year, unknown assailants bundled him into the back of a car and drove him to an isolated spot near Yaounde airport. They beat him with stones and batons and left him for dead, he said.
Chouta is one of several reporters who have been beaten or killed. Two journalists were killed in the last month, prompting condemnation from the United Nations.
"If he (Biya) loves Cameroonians, let him fix things and go. The woes are deep," Chouta told Reuters.
Kouam Yves, a motorcycle taxi driver, is critical of Biya and what he describes as rampant corruption. But he paused as he spoke, worried about who might be listening.
"I can't celebrate the Head of State's birthday. For more than 20 years, I have not seen anything which we have executed in this country that went well like in other countries," he said.
Walla stated that at 90, Biya should spend his days playing with his grandchildren.
A government spokesperson did not respond to calls requesting comment.