The secret sauce of games

Here are links to game with source code and also documentation about the game formats. Some of them are commercial games that have released source code and other are ones that was open source. Links to more games can be found at http://osgameclones.com.

The Man Behind The Curtain

A

• Arx Fatalis – http://www.arkane-studios.com/uk/arx_downloads.php
• Alien Vs Predator - https://github.com/miohtama/aliens-vs-predator
• Age of Empires II - https://github.com/SFTtech/openage
• Abuse - https://github.com/osgcc/abuse

C

• C&C Red Alert -
  • OpenRA - Open Sourc C&C Red Alert

D

• Descent – https://github.com/osgcc/descent-pc
• Descent 2 – https://github.com/osgcc/descent2
• Doom – https://github.com/id-Software/DOOM
• http://aiforge.net/test/wadview/dmspec16.txt
• http://doomwiki.org/wiki/WAD
• http://glbsp.sourceforge.net/
• DOOM 3 – https://github.com/id-Software/DOOM-3
• Duke Nukem 3D – ftp://ftp.3drealms.com/source/duke3dsource.zip

E

• Enemy-Territory – https://github.com/id-Software/Enemy-Territory

F

• Freeciv – http://sourceforge.net/projects/freeciv/
• FreeSpace 2 - http://svn.icculus.org/fs2open/

H

• Heretic / Hexen – http://sourceforge.net/projects/heretic/
• homeworld - https://github.com/aheadley/homeworld

J

• Jedi Knight III: Jedi Academy - https://github.com/OpenSourcedGames/jedi_academy
• Jedi Knight II: Jedi Outcast - https://github.com/PJayB/jk2src

M

• Meridian 59 - https://github.com/Meridian59/Meridian59
  • Miner Wars 2081 - https://github.com/KeenSoftwareHouse/Miner-Wars-2081
• Morrowind - https://openmw.org

N

• No one lives forever - https://github.com/osgcc/no-one-lives-forever
• No one lives forever 2 - https://github.com/wilkie/no-one-lives-forever-2

P

• Penumbra Overture - https://github.com/FrictionalGames/PenumbraOverture
• Postal - https://bitbucket.org/gopostal/postal-1-open-source/src
• Prince of Persia - https://github.com/jmechner/Prince-of-Persia-Apple-II

U

• Ultima 7
  • http://sourceforge.net/projects/exult/develop
  • Ultima VII Internal Formats
• Ultima 8
  • http://sourceforge.net/p/pentagram/code/HEAD/tree/
  • Ultima VIII Internal Formats
  • Ultima IX
  • Ultima IX Internal Formats
    • Exult – http://exult.sourceforge.net/
• Ultima Underworld
  • Ultima Underworld 1 and 2 Formats Specification
  • Ultima Underworld Internal Formats

Q

• Quake – https://github.com/id-Software/Quake
• http://www.gamers.org/dEngine/quake/spec/quake-spec34/qkmenu.htm
  • Ramblings in Realtime - 2000
    • Chapter 1 - Inside Quake: Visible-Surface Determination
    • Chapter 2 - Consider the Alternatives - Quake's Hidden Surface Removal
    • Chapter 3 - Sorted Spans in Action
    • Chapter 4 - Quake's Lighting Model: Surface Caching
    • Chapter 5 - Surface Caching Revisited, Quake's Triangle Models, and More
    • Chapter 6 - Quake's 3-D Engine: The Big Picture
• Quake 2 – https://github.com/id-Software/Quake-2
• http://www.flipcode.com/archives/Quake_2_BSP_File_Format.shtml
• Quake-III-Arena – https://github.com/id-Software/Quake-III-Arena
• https://github.com/mikezila/uQuake3

R

• Return to Castle Wolfenstein – https://github.com/id-Software/RTCW-SP
• Rise of the Triad – https://github.com/OpenSourcedGames/Rise-of-the-Triad

S

• Serious Same - Serious Engine
• Shadow Warrior – ftp://ftp.3drealms.com/source/shadowwarriorsource.zip
• scummvm - https://github.com/scummvm/scummvm
• Simcity - https://github.com/SimHacker/micropolis
• Shadowgrounds - https://github.com/vayerx/shadowgrounds

T

• Tomb Raider
• Open Tomb
• OpenLara

W

• Wolfenstein 3D - https://github.com/id-Software/wolf3d

X

• X-Com - https://github.com/SupSuper/OpenXcom