"ok: A sheep game" is a procedurally generated, real time strategy RPG prototype made by @that-ben in early 2021 for B&W Macs in which you incarnate a shepherd, rescuing lost sheep and bringing them back to your house.  You...

The Oregon Trail II is an enhanced remake of The Oregon Trail and the 25 Anniversary Limited Edition CD includes both the new and original versions for Macintosh, Windows, and MS-DOS, even if it is so low-key about it that the only mention of the...

Operation Neptune is an educational game for children 5 to 9 featuring math solving problems with a submarine storyline.    

Ported by Rockstar Games. A dark future. An uncertain past. No one left to trust. An intense action anime thriller comes to life in Oni. As an elite member of the tech-crimes task force, Konoko is an agent on a mission to fight the evil...

On-The-Contrary is one of the first games on Macintosh and certainly the first of the memory genre on Mac, dating back to May 25th, 1984, only 4 months after the very first Macintosh was released.  In the game On-the-Contrary, each player (up...

Open Sonic is an open-source game based on the "Sonic the Hedgehog" universe. It introduces a different style of gameplay called cooperative play, in which it's possible to control 3 characters simultaneously. Unlike most...

OpenTTD ("Open Transport Tycoon Deluxe") is a freeware, open-source remake of the traffic simulator from 1995. It greatly expands the original game, featuring lots of new additions and maps several times larger in size. The...

For devotees of fantasy role-playing adventure comes OrbQuest: The Search for Seven Wards. You seek a magical orb shattered into seven parts, the Seven Wards, which must be gathered from far and wide to restore the orb and defeat evil. The Search...

Someone has broken into the Museum of the History of Cypriot Coinage and all the rare coins have mysteriously vanished. Your mission is to travel back in time with your time machine to recover all 100 missing coins. In your quest you will have the...

Oscar The Balloonist: My Creative Workshop is a collection of artistic activities and mini games for young children.  - (MobyGames)

Carmela, Oscar the balloonist's treasure chest, has gone missing. When he lands his balloon and finds her in the woods, she refuses to leave until he has solved all the puzzles. The forest and its animals come to life in each of the four seasons...

Oscar the Balloonist Dives into the Lake follows the further adventures of the young hero of Oscar the Balloonist and the Secrets of the Forest as he heads to the lake to visit Balthasar Pumpernickel, an animal researcher. Balthasar...

In Oscar the Balloonist Flies into the Mountains the player takes control of Oscar who visits the mountains together with the scientist Balthasar. By clicking on items in two screens (house and mountains) the player learns facts about the...

Oscar the Balloonist Drops into the Countryside takes the player on another adventure with the character Oscar the Balloonist. This time he leaves the town to learn about animals living in the countryside, as well as to help his friend...

In Oscar the Balloonist Discovers the Farm the player takes control of Oscar who crashes his balloon into a farm. There he meets Balthasar who researches farm animals. By clicking on items in three screens (office, kitchen and farm) the...

Odamex is a free, cross-platform (Mac, Windows, Linux) modification of the Doom engine that allows players to easily join servers dedicated to playing Doom online.  - (Odamex.net) *This is an unofficial port by thedoctor45 for Mac OS X...

An Open Source 90s Pixelart Science-Fiction Real-Time Strategy game with Multiplayer (LAN and internet) support, competent skirmish AI as well as an integrated map editor.  All the assets are licensed...