Long before the time in which the game is set, two extremely powerful races, the Orions and the Antarans, fought a war that devastated most of the galaxy. The victorious Orions, rather than exterminate the Antarans, imprisoned them in a pocket dimension before departing the galaxy, leaving behind a very powerful robotic warship, the Guardian, to protect their homeworld. Some time after the game starts, the Antarans, having broken out of their prison dimension, begin to send increasingly powerful fleets to destroy the players' colonies.
Master of Orion II: Battle at Antares (a.k.a. MoO2) is a turn-based 4x strategy game set in space. Despite the game's name, conquering the Orion star system does not automatically win the game, although the benefits acquired from doing so makes it quite easy. There are three ways to win the game - exterminate all opponents; get elected as the supreme leader of the galaxy; or lead a successful assault against the Antaran homeworld. To get elected as the supreme leader, you need two-thirds of the total votes, and each empire's votes are based on its population. So getting elected requires some combination of conquest and diplomacy. To carry the battle to the Antaran home universe you first need to obtain the technology of the Dimensional Portal and build it.
Master of Orion II: Battle at Antares was the first sequel to Master of Orion. Like the original, it was developed by Simtex and designed by Steve Barcia and Ken Burd. The Windows 95 and MS-DOS versions of the game were published (both on one cd-rom) by Microprose in November 1996, while the Apple Macintosh version was published almost a year later by MacSoft. Master of Orion II won the Origins Award for "Best Fantasy or Science Fiction Computer Game of 1996".
The last official patch by Microprose for the PC from April 1997 updates both DOS Orion2 and Windows Orion95. If you have installed MoO2 from an original cd-rom, then you need to apply this patch first.
moo2v131.zip or moo2v131.zip
Fan patch that fixes important game bugs and introduces new game features, like the galaxy size 'Cluster' and technology age 'Post-warp'. Only for the English DOS version. The English DOS version of Master of Orion II that is sold online is patch version 1.40.b23 from May 2006. An update to the patcher program from 2008 does not add new fixes to the game itself but does change the version number to 1.40.b24.
Lord Brazen's blog has a faq with more detailed information about his patch.
New fan patch for the English, German, French, Spanish and Italian DOS versions. Fixes most known crashes, stalls and network synchronization errors, as well as an abundance of lesser bugs. Introduces new features like the option to play against a random number of opponents, and interface enhancements reducing micromanagement like new keyboard shortcuts and customizable build queue lists. The patch supports modding via plain text configuration files. By default 'SET150.CFG' is loaded that enables improved AI ship designs and a Heroes3 combat initiative system (YouTube video). SET150 can be disabled should you prefer a classic 1.40-like game experience or you can write your own config to fully customize your game!
The big manual contains detailed descriptions of bug fixes, new game mechanics and modding options:
You are an uncreative telepath, starting in a corner of a large galaxy. Can you win within 100 turns? To play, download the zip and extract. It contains 2 save games, one for version 1.31/1.40 and one for v1.50. Rename the appropriate version to SAVE10.GAM and copy it to your MoO2 folder. Then load save 10 from the universal menu and start!
SAVE10_OC1_Kraft.zip (87 downloads; 95 kB.)
You play an uncreative race, starting in an isolated region of space. Can you get out, and if you do what resistance will you meet? To play, download the file, rename it to SAVE10.GAM and copy it to your MoO2 folder. Then load save 10 from the universal menu and start!
SAVE10_OC2_Rocco.GAM (70 downloads; 204 kB.)
You start in a system with five good planets, but the galaxy only contains three stars! To play, download the zip and extract. It contains 2 save games, one for version 1.31/1.40 and one for v1.50. Rename the appropriate version to SAVE10.GAM and copy it to your MoO2 folder. Then load save 10 from the universal menu and start!
SAVE10_3_STARS.zip (70 downloads; 60 kB.)
In response to a request on Reddit, I have adapted the old Defensive Anti-Blitz Mod by Jukka Mikkonen to run on 1.50. I haven't changed it much, mostly enabled the new 1.50 combat mechanics and corrected a few issues with the original mod. Highlights: Missile Base has 800 (instead of 300) space units - An upgrade to ship hit points, and even larger for star bases - Strong ground installation with 10x the hit points - Severely upgraded space monsters & Guardian of Orion, damagewise - Antarans should prove to be a threat once again - A few automatic techs, such as Auto-Factory, Fighter Bays, Fighter Garrison, Reinforced Hull and Heavy Armor.
DAB.zip v2 (77 downloads; 87 kB.)
Vanilla+ is a light balance mod included with the 1.50 patch that features rebalanced custom race picks, subtly enhanced map generation and no more 1-pop tiny planets, stronger planetary defenses, star bases and missile bases that can fire torpedoes, cheaper Marine & Armor Barracks, and slightly stronger AI opponents. It can be enabled from ORION2.CFG.
Very extensive mod, that changes many aspects of the game. ICE aims to create a new and more challenging single player game. Initially released on Feb 17, 2015, the mod has undergone many revisions since then and currently stands at version 14b. Patch 1.50.7 or higher is required for ICE 14b to run.
Redesigned stock races; stronger AI opposition; revalued race ability costs (45 picks: 24 base and 21 negatives instead of 10 base and 10 negatives); revamped tech tree; beefed up Guardian; more threatening Antarans and a grand finale when invading the Antaran home world!
ICE-X is similar to ICE-M except that it has AI opponents with more raw power, further increasing the difficulty level. Both versions are part of the same download package. Choose your preferred version in the ORION2 configuration file.
How to install the ICE mod video.