| Observation | Devolver Digital | 8/10 | |
| Observer | Bloober Team | 6/10 | |
| Observer: System Redux | Bloober Team | 7/10 | |
| Oceanhorn 2: Knights of the Lost Realm | Cornfox & Bros. | 5/10 | |
| Oceanhorn: Monster of Uncharted Seas | Cornfox & Bros. | 7/10 | |
| Oceanhorn: Monster of Uncharted Seas (Second Opinion) | Cornfox & Bros. | 6/10 | |
| Oceanhorn: Monster of Uncharted Seas | Cornfox & Bros. | 5/10 | |
| Oceanhorn: Monster of Uncharted Seas | Cornfox & Bros. | 7/10 | |
| Oceanhorn: Monster of Uncharted Seas | Cornfox & Bros. | 6/10 | |
| Octahedron | Square Enix | 8/10 | |
| Octahedron: Transfixed Edition | Square Enix | 8/10 | |
| Octodad: Dadliest Catch | Young Horses | 8/10 | |
| Octodad: Dadliest Catch | Young Horses | 7/10 | |
| Octopath Traveler | Square Enix | 9/10 | |
| Octopath Traveler | Square Enix | 8/10 | |
| Octopath Traveler II | Square Enix | 7/10 | |
| Oddworld: Abe's Oddysee | GT | 9/10 | |
| Oddworld: Abe's Oddysee - New 'n' Tasty! | Oddworld Inhabitants | 8/10 | |
| Oddworld: Abe's Oddysee - New 'n' Tasty! | Oddworld Inhabitants | 8/10 | |
| Oddworld: Abe's Oddysee - New 'n' Tasty! | Oddworld Inhabitants | 8/10 | |
| Oddworld: Abe's Oddysee - New 'n' Tasty! | Oddworld Inhabitants | 7/10 | |
| Oddworld: Abe’s Oddysee - New 'n' Tasty! | Oddworld Inhabitants | 7/10 | |
| Oddworld: Munch’s Oddysee | Oddworld Inhabitants | 4/10 | |
| Oddworld: Soulstorm Enhanced Edition | Oddworld Inhabitants | 6/10 | |
| Odin Sphere Leifthrasir | NIS America | 9/10 | |
| Odin Sphere Leifthrasir | NIS America | 9/10 | |
| Odin Sphere Leifthrasir (Second Opinion) | NIS America | 9/10 | |
| Odium to the Core | QubicGames | 5/10 | |
| Odysseus Kosmos and his Robot Quest: Episode 1 | HeroCraft | 7/10 | |
| Ogre Battle 64: Person of Lordly Caliber | Square Enix | 8/10 | |
| Oh My Godheads | Square Enix | 5/10 | |
| Oh...Sir!! The Insult Simulator | Vile Monarch | 7/10 | |
| Okamiden | Capcom | 8/10 | |
| Old Man's Journey | Broken Rules | 4/10 | |
| Old Man's Journey | Broken Rules | 6/10 | |
| Old Time Hockey | V7 Entertainment | 7/10 | |
| OlliOlli: Switch Stance | Gambitious Digital | 8/10 | |
| Olympia Soiree | Aksys | 6/10 | |
| Omega Labyrinth Life | D3 Publisher | 8/10 | |
| Omega Pattern HD | Borokai Studio | 7/10 | |
| Omega Zodiac | Proficient City | 3/10 | |
| Omen of Sorrow | EastAsiaSoft Limited | 5/10 | |
| Omensight | Spearhead | 7/10 | |
| Omensight | Spearhead | 6/10 | |
| One Dog Story | Big Way | 6/10 | |
| One Night Stand | Ratalaika Games | 8/10 | |
| One Night Stand | Ratalaika Games | 6/10 | |
| One Piece: Burning Blood | Bandai Namco | 6/10 | |
| One Piece: Burning Blood | Bandai Namco | 6/10 | |
| One Piece: Pirate Warriors 3 | Bandai Namco | 8/10 | |
| One Piece: Pirate Warriors 4 | Bandai Namco | 7/10 | |
| One Piece: Romance Dawn | Namco Bandai | 3/10 | |
| One Piece: Unlimited Cruise SP | Namco Bandai | 4/10 | |
| One Piece: Unlimited World Red | Namco Bandai | 8/10 | |
| One Piece: Unlimited World Red Deluxe Edition | Bandai Namco | 7/10 | |
| One Piece: Unlimited World Red Deluxe Edition | Bandai Namco | 7/10 | |
| One Punch Man: A Hero Nobody Knows | Bandai Namco | 5/10 | |
| One Upon Light | Rising Star Games | 7/10 | |
| One Upon Light | Rising Star Games | 7/10 | |
| One Way Heroics | Playism | 5/10 | |
| One-Way Ticket | Zodiac Interactive Limited | 8/10 | |
| Onechanbara Z2: Chaos | NIS America | 6/10 | |
| Onee Chanbara ORIGIN | D3 Publisher | 5/10 | |
| OneShot | Degica | 8/10 | |
| oOo: Ascension | Extra Mile Studios | 5/10 | |
| Operation Abyss: New Tokyo Legacy | NIS America | 5/10 | |
| Operation Babel: New Tokyo Legacy | NIS America | 3/10 | |
| Operencia: The Stolen Sun | Zen | 7/10 | |
| Oppaidius Desert Island! | Vittorio Giorgi | 6/10 | |
| Oppaidius Summer Trouble! | Vittorio Giorgi | 7/10 | |
| Oppaidius Tropical Cruise! | Vittorio Giorgi | 7/10 | |
| Orcs and Elves | EA | 8/10 | |
| Orcs Must Die! | Robot | 7/10 | |
| Order of the Thorne: The King’s Challenge | Infamous Quests | 4/10 | |
| Ori and the Blind Forest | Microsoft Game Studios | 9/10 | |
| Ori and the Blind Forest: Definitive Edition | Xbox Game | 9/10 | |
| Ori and the Will of the Wisps | Xbox Game Studios | 9/10 | |
| Ori and the Will of the Wisps | Xbox Game | 9/10 | |
| Oriental Empires | Iceberg | 5/10 | |
| Original Journey | Another Indie | 5/10 | |
| Osu! Tatakae! Ouendan | Nintendo | 9/10 | |
| Othello | Arc System Works | 6/10 | |
| Othercide | Focus Home | 6/10 | |
| Out of Order | Hungry Software | 8/10 | |
| Out There: Omega Edition | Mi-Clos Studio | 5/10 | |
| Outbreak: The New Nightmare | Dead Drop Studios LLC | 2/10 | |
| OUTBUDDIES | Headup | 6/10 | |
| Outer Wilds | Annapurna | 5/10 | |
| Outlast: Bundle of Terror | Red Barrels | 7/10 | |
| Outriders | Square Enix | 5/10 | |
| Overcooked | Team17 | 8/10 | |
| Overcooked | Team17 | 8/10 | |
| Overcooked! 2 | Team17 | 8/10 | |
| Overcooked! 2 – Surf 'n' Turf | Team17 | 7/10 | |
| Overcooked! All You Can Eat | Team17 | 9/10 | |
| Overcooked! Special Edition | Team17 | 6/10 | |
| Overcooked: The Lost Morsel | Team17 | 7/10 | |
| Overfall | Pera Games | 7/10 | |
| Overgrowth | Wolfire | 6/10 | |
| Overlord: Minions | Codemasters | 7/10 | |
| Overpass | Nacon | 5/10 | |
| Overwatch | Blizzard | 8/10 | |