Can You Defeat Voldemort in Harry Potter Video Games?

Yes—in most mainline adaptations of the books/films:

Games Where You Fight & Defeat Voldemort

• Philosopher's Stone (2001) – Final duel in Mirror of Erised chamber.
• Chamber of Secrets (2002) – Basilisk fight → Riddle memory (young Voldemort).
• Prisoner of Azkaban (2004) – Sirius/Black duel; Voldemort not directly fought.
• Goblet of Fire (2005) – Graveyard duel vs. resurrected Voldemort.
• Order of the Phoenix (2007) – Ministry atrium duel.
• Half-Blood Prince (2009) – Astronomy Tower / cave sequences.
• Deathly Hallows – Part 2 (2011) – Final showdown in Great Hall.
• LEGO Harry Potter Years 1-4 / 5-7 – Playable Voldemort fights in multiple levels.

Games Without Direct Voldemort Battle

• Quidditch World Cup (2003) – Sports only.
• Hogwarts Mystery (mobile, 2018) – Narrative RPG; you influence but don't duel him directly.
• Wizards Unite (AR, 2019) – Fortress battles vs. Death Eaters, not Voldemort.

Nearly every story-mode HP game culminates in a Voldemort confrontation.