Free / open source games: M - O

There are more and more free / open source games: this list, far from being exhaustive but continuously growing, gives priority to projects that keep on being developed and is meant to help whoever is looking for some fun.

All these open source games are free but remember that the term free is meant as in "free speech", not as in "free beer" so if you like one of these games please try to contribute to its development: some teams need varioul kinds of help (programmers, graphics experts...), some accepts donations to finance the development of a game, some need help to test new versions which means that you can have fun and at the same time help the development of a project.

This is the fourth part of the list and included the games from M to O: from the side menu you can access to all the other parts of the list.

Mah-Jong is an implementazion of the Chinese Classical version of the game. There is a server program, which handles the game, an X client to allow humans to play naturally, and a computer player.

Operating systems: Windows, Linux

Latest version: 1.10 (July 10 2009)

M.A.R.S. is a 2D shoot-em-up set in the year 3547 in aa galaxy where an interstellar war starts. Players can take part to space battles or gladiators fights.

Operating systems: Windows, Linux

Latest version: 0.61 (December 6 2010)

M.A.X. (Mechanized Assault and eXploration) Reloaded is a fanmade strategy game and a remake of the old M.A.X. by Interplay. The game can be played in a turn-based mode or simultaneous mode and features combat in air, land, and sea.

Operating systems: Windows, Linux, Mac OS X, Amiga OS 4

Latest Version: 0.2.6 (August 25 2009)

MegaGlest is an open source 3D-real-time strategy game derived from Glest with the goal of enhancing its features. You control the armies of one of six different factions: Tech, Magic, Egyptians, Indians, Norsemen Persian or Romans. Different resources have to be gathered by every faction.

Operating systems: Linux, Windows

Latest Version: 3.6.0 (December 4 2011)

Mega Mario is a Super Mario Bros. 1 clone with various improvements starting from the graphics. It also features a blood-mode, which makes killed enemies spread their blood all over the level.

Operating systems: Linux, Windows

Latest version: 1.6 (March 26 2009)

Hardware/software requirements: graphics card with 3D acceleration

MegaMek is a turn-based strategy game and a free unofficial version of Classic BattleTech where a war is fought with giant robots, tanks and infantry.

Operating systems: all the ones with Java support

Latest Version: 0.35.25 (October 9 2011)

Menace of the Mines is a fast-paced roguelike game that has tons of monsters, many different classes and races and a unique magic system.

Operating systems: Linux, Windows

Latest Version: 0.5 (July 25 2010)

Minetest is one of the first InfiniMiner/Minecraft(/whatever) inspired games, with a goal of taking the survival multiplayer gameplay to a slightly different direction.

Operating systems: Linux, Windows

Latest Version: 0.4.11 (December 26 2014)

Monster 2 is a nostalgic trip back to the days of the epic SNES RPGs like Final Fantasy and Breath of Fire. It was built from scratch with a focus on a good story, unique gameplay features, and professional looking and sounding artwork and audio.

Operating systems: Linux, Windows, Mac OS X

Latest Version: 2.0 (November 4 2010)

MoonPy is an open source remake of the turn based strategy game Moonbase Commander. Each player controls a main hub which can send out other hubs, attack enemy structures, create defensive buildings, and collect energy for further expansion; this is accomplished through launching buildings and/or weapons from a hub.

Operating systems: Windows, Linux, Mac OS X

Latest Version: 0.8.21 (March 27 2010)

Hardware/software requirements: python and pygame support

Morris is an implementation of the board game "Nine Men's Morris". Other names for this game are: Mills, Merrills, Morris, or Mühle in German. Nine Men's Morris, being probably 2000-3000 years old, appears to be one of the oldest board games, much older than chess.

Among others, the game plays the following variants:

• Lasker variant (moves are also allowed in the set-phase)
• the Möbius board
• the Windmill board
• Pentagon and Hexagon boards
• Morabaraba
• Six and Seven Men's Morris
• Tapatan, Achi, Nine Holes

Operating systems: Linux, Windows

Latest Version: 0.2 (October 25 2009)

Mtp Target is an online multiplayer action game where you roll down a giant ramp and try to land softly on the platform that gives you the most points while at the same time you try to eject your opponents.

Operating systems: Linux, Windows, Mac OS

Latest Version: 1.5.19 (September 19 2008)

NAEV is a game inspired to Escape Velocity. In a galaxy to explore players must face many battles but there are also chances for trading.

Operating systems: Windows, Linux, Mac OS X

Latest Version: 0.5.3 (April 15 2012)

Hardware/software requirements: 512 MB RAM, 150 MB hard disk, graphics card with OpenGL support

netPanzer  is an online multiplayer tactical warfare game designed for fast action combat. Gameplay concentrates on the core - no resource management is needed. The game is based on quick tactical action and unit management in real-time. Battles progress quickly and constantly as destroyed players respawn with a set of new units.

Operating systems: Windows, Linux, Mac OS X

Latest Version: 0.8.3 (February 20 2010)

Neverball is a part puzzle part action game where the player must move a ball through an obsacle course before time runs out.

With Neverball there's Neverputt, a miniature golf game using Neverball phisics and elements.

Operating systems: Windows, Linux, Mac OS X, FreeBSD

Latest Version: 1.5.4 (September 20 2009)

Hardware/software requirements: 500 MHz CPU, graphics card with OpenGL support

Nexuiz is a standalone 3D FPS based on the DarkPlaces graphic engine, derive from the Quake one. It's possibile to play it in single player mode but also in deathmatch or capture the flag modes, also online.

Operating systems: Windows, Linux, OS X.

Latest Version: 2.5.2 (October 1 2009)

Hardware/software requirements: 1 GHz CPU, 512 MB RAM, 400 MB hard disk, graphics card with 3D acceleration

NLarn is a Roguelike game started as a remake of Larn then adding an advanced user interface and various extensions.

Operating systems: Windows, Linux

Latest Version: 0.72 (July 6 2011)

NullpoMino is a Tetris clone with a number of play modes and che possibility to play over the Internet or LAN.

Operating systems: all the ones with Java support

Latest Version: 7.5.0 (January 21 2011)

Hardware/software requirements: Java

OpenAnno is a realtime economy simulation game with strategy elements.

Operating systems: Windows, Linux

Latest Version: 2008.1 (October 1 2008)

OpenArena is a 3D standalone FPS inspired to Quake III Arena and uses its graphic engine but with free components only. Besides the classic single player mode it's possibile to play it in deathmatch or capture the flag modes, also online with several variants that includes the ones contained in the expansion pack Quake III Team Arena.

The  Open Arena Fortress mod adds customizable player-classes to Open Arena. You can
choose from familiar presets, such as "Soldier" or "Sniper," or create your own class by selecting your starting weapons and armor-class.

A review of the game is available.

Operating systems: Windows, Linux, Mac OS X, FreeBSD, Solaris.

Latest Version: 0.8.8 (February 20 2012)

Hardware/software requirements: 233 MHz CPU, 128 MB RAM, 300 MB hard disk, graphics card with 3D acceleration

OpenClonk the Open source successor of the Clonk gaming series. It's a multiplayer-action-tactic-skill game. It is often referred to as a mixture of The Settlers and Worms. The game encourages free play but the normal goal is to build a mine and exploit the earth from valuable resources.

Operating systems: Windows, Linux

Latest Version: 1.1.3 (December 28 2010)

OpenDungeons is an open source, real time strategy game based on the Dungeon Keeper series of games. Players build an underground dungeon which is inhabited by creatures. Players fight each other for control of the underground by indirectly commanding their creatures, directly casting spells in combat, and luring enemies into sinister traps.

Operating systems: Windows, Linux

Latest Version: 0.4.8 (April 25 2011)

Open Sonic is a game based on the "Sonic the Hedgehog" universe. It has a jump'n'run game base but the player also need a strategy to geth through the levels.

Operating systems: Windows, Linux, Mac OS X, Dreamcast

Latest Version: 0.1.2 (July 23 2009)

Hardware/software requirements: graphics card with 3D acceleration, Allegro graphics library

OpenSSN is a submarine simulator (sometimes referred to as a subsim) for modern classes of submarine. The player is able to pilot their submarine, detect vessels and engage enemy ships. The game focuses on the tactical aspect of commanding a submarine, leaving many of the minor details up to the AI crew.

Operating systems: Windows, Linux, Mac OS X, FreeBSD

Latest Version: 0.8 (September 18 2011)

Hardware/software requirements: graphics card with 3D acceleration

OpenTTD is a free clone of the old game "Transport Tycoon Deluxe", where the player must develop a transport company.

Operating systems: Windows, Linux, Mac OS X, FreeBSD, OpenBSD, NetBSD, Solaris

Latest Version: 1.4.0 (April 1 2014)

OpenTyrian is a port of the DOS shoot-em-up Tyrian. Jason Emery generously gave the OpenTyrian developers a copy of the Tyrian 2.1 source code.

Operating systems: Windows, Linux

Latest Version: 2.1.20130907 (September 7 2013)

OpenXcom is an open-source reimplementation of the game "UFO: Enemy Unknown" (also known as "X-Com: UFO Defense") with the goal to bring back the tried and true feel of the original with greater flexibility and moddability.

Operating systems: Windows, Linux, Mac OS X

Latest Version: 1.0 (June 13 2014)

Open Yahtzee is an open-source (free) version of the classic dice game Yahtzee.

Operating systems: Windows, Linux

Latest Version: 1.9 (April 20 2009)