| Otto and the Ancient Worlds (2022) | 1,419 | 8 |
| Otto Matic (2001) | 14,565 | 56 |
| Otto's Escape (2024) | 22 | 2 |
| OTTTD (2014) | 3,997,899 | 236 |
| OTXO (2023) | 196,458 | 238 |
| Oubliette (1983) | 27,966 | 65 |
| Ougon no Kizuna (2009) | 18,918 | 8 |
| Ouija Escape VR (2024) | 0 | 0 |
| OUMUAMUA (2024) | 4,896,877 | 73 |
| Ounba (2026) | 0 | 0 |
| Our Adventurer Guild (2024) | 225,986 | 522 |
| Our Darker Purpose (2014) | 1,391,227 | 681 |
| Our Dying World (2023) | 8,890 | 31 |
| Our Elusive Suffering (2022) | 130,658 | 35 |
| Our End of the World (2017) | 464 | 10 |
| Our Ephemeral Nights (2025) | 0 | 0 |
| Our Freedom (2025) | 342,792 | 30 |
| Our Hero! Last (2022) | 18 | 4 |
| Our Hero! Two (2021) | 128 | 5 |
| Our Home, My Keeper (2026) | 51 | 1 |
| Our House Party (2009) | 4,233 | 5 |
| Our House Party! (2009) | 14,904 | 42 |
| Our Life: Beginnings & Always (2020) | 339,265 | 1,620 |
| Our Life: Now & Forever (2026) | 485 | 10 |
| Our Love Will Grow (2015) | 187,928 | 58 |
| Our Lovely Escape (2019) | 11,898 | 40 |
| Our Savior: Recorn Culted (2021) | 148,587 | 20 |
| Our Secret Below (2020) | 4,353,818 | 328 |
| Our Two Bedroom Story (2016) | 11,850 | 26 |
| Our Wonderful World (2016) | 3,002 | 4 |
| Our world has not decayed (2019) | 369 | 3 |
| Our World is Ended (2017) | 168,000 | 347 |
| Our World Is Ended. (2017) | 421,860 | 912 |
| Ourea (2020) | 9,263 | 28 |
| The Ouroboros King (2023) | 2,173,134 | 126 |
| Ouroboros: Prelude (2017) | 1,227 | 4 |
| ourWorld (2007) | 501,943 | 32 |
| Out and About (2025) | 118,231 | 106 |
| Out Board (1990) | 1,185,320 | 25 |
| Out Live (1989) | 824,747 | 182 |
| Out of Gas (1992) | 2,782,961 | 211 |
| Out of Hand: Deluxe (2025) | 9 | 1 |
| Out Of Hands (2025) | 314,188 | 21 |
| Out of Line (2021) | 2,413,745 | 1,291 |
| Out of Nowhere (2024) | 17,432,773 | 1,041 |
| Out of Ore (2022) | 5,214,301 | 2,691 |
| Out of Reach (2015) | 5,879,398 | 788 |
| Out of Reach: Treasure Royale (2020) | 468,306 | 155 |
| Out of Sight (2021) | 4,304,615 | 1,500 |
| Out of Space (2019) | 19,444,563 | 1,467 |
| Out of Stock! (2025) | 5,488 | 3 |
| Out of the Box (2018) | 11,522,562 | 291 |
| Out of the Park Baseball (1999) | 1,176,637 | 3,507 |
| Out of the Park Baseball 10 (2009) | 0 | 0 |
| Out of the Park Baseball 11 (2010) | 33,829 | 1 |
| Out of the Park Baseball 12 (2011) | 17,208 | 3 |
| Out of the Park Baseball 13 (2012) | 35,635 | 10 |
| Out of the Park Baseball 14 (2013) | 21,544 | 7 |
| Out of the Park Baseball 15 (2014) | 354,461 | 129 |
| Out of the Park Baseball 16 (2015) | 445,752 | 178 |
| Out of the Park Baseball 17 (2016) | 381,462 | 356 |
| Out of the Park Baseball 18 (2017) | 597,938 | 809 |
| Out of the Park Baseball 19 (2018) | 839,958 | 597 |
| Out of the Park Baseball 2 (2000) | 15 | 1 |
| Out of the Park Baseball 20 (2019) | 1,062,374 | 443 |
| Out of the Park Baseball 21 (2020) | 1,347,906 | 1,789 |
| Out of the Park Baseball 22 (2021) | 1,847,803 | 1,782 |
| Out of the Park Baseball 3 (2001) | 0 | 0 |
| Out of the Park Baseball 4 (2002) | 0 | 0 |
| Out of the Park Baseball 5 (2003) | 0 | 0 |
| Out of the Park Baseball 6 (2004) | 23 | 1 |
| Out of the Park Baseball 6.5 (2005) | 0 | 0 |
| Out of the Park Baseball 8 (2007) | 137 | 1 |
| Out of the Park Baseball 9 (2008) | 0 | 0 |
| Out of the Park Baseball Manager 2006 (2006) | 0 | 0 |
