Game Files Extensions - What are game files and how do I open a game file?

What are game files and how do I open a game file?

File Type Category File Format
.a52 Game Files Atari 5200 ROM
.abs Game Files AB SuDoKu Saved Game
.bf Game Files CryoBF Game Data File
.bfg Game Files Big Fish Games Application File
.bgl Game Files Flight Simulator Scenery File
.big Game Files Electronic Arts Game Data File
.biq Game Files Civilization 3 Scenario File
.civ5save Game Files Civilization 5 Saved Gae
.dat_old Game Files Minecraft Level.dat Backup File
.ddt Game Files Football Manager Keep Player Data File
.dem Game Files Video Game Demo File
.dff Game Files RenderWare Model File
.dmo Game Files Duke Nukem 3D Demo File
.ess Game Files The Elder Scrolls Saved Game
.fbrb Game Files Battlefield Bad Company 2 Data File
.fpk Game Files Civilization 4 Data File
.gam Game Files Saved Game File
.gb Game Files Game Boy ROM File
.gba Game Files Game Boy Advance ROM
.gbc Game Files Game Boy Color ROM
.gc Game Files Galactic Conquest Saved Game
.gcf Game Files Game Cache File
.gct Game Files Ocarina Cheat Code Manager File
.grp Game Files StarCraft Graphics Group File
.h3m Game Files Heroes 3 Map File
.hog Game Files Descent Mission File
.hpk Game Files Tropico Game Archive
.inv Game Files INVedit File
.iwd Game Files Call of Duty Game Data File
.map Game Files Quake Engine Map File
.mas Game Files rFactor Track File
.mca Game Files Minecraft "Anvil" Map File
.mdl Game Files Half-Life Model File
.mpq Game Files Blizzard Mo'PaQ File
.narc Game Files Nintendo DS Archive File
.naz Game Files Total Overdose Game Data File
.nds Game Files Nintendo DS Game ROM
.nes Game Files Nintendo (NES) ROM File
.pak Game Files Video Game Package
.pcf Game Files Valve Particle System File
.pk3 Game Files Quake 3 Engine Game Data File
.plr Game Files rFactor Player File
.psv Game Files PlayStation 2 Save File
.puz Game Files Across Lite Crossword Puzzle
.rbz Game Files SketchUp Plug-in
.rez Game Files Lithtech Game Engine Resource File
.s2z Game Files Heroes of Newerth Game Data File
.sad Game Files Black & White Audio File
.sav Game Files Saved Game
.scn Game Files Age of Mythology Scenario File
.scs Game Files SimCity Societies Saved Game File
.scs Game Files Prism3D Game Data File
.sdz Game Files Spring Content Package
.sfb Game Files PlayStation 3 Disc Data File
.smc Game Files Super Nintendo Game ROM
.sow Game Files Descent ARJ Archive
.spb Game Files Flight Simulator Mission File
.steamstart Game Files Valve Steam Start File
.tlk Game Files BioWare Aurora Engine Talk Table File
.unity3d Game Files Unity Web Player File
.upk Game Files Unreal Engine 3 Package
.viv Game Files Need for Speed Car Data File
.w3x Game Files Warcraft 3 Expansion Map FIle
.wad Game Files Doom WAD File
.wotreplay Game Files World of Tanks Replay File
.wrpl Game Files Widelands Saved Game File
.wz Game Files MapleStory Game Data File
.xds Game Files DS Game Maker Project File
.xex Game Files Xbox 360 Executable File
.xmb Game Files Age of Empires Game Data File
.xnb Game Files XNA Game Studio Binary Package
.xpk Game Files WWE RAW Model File
.z64 Game Files Nintendo 64 Game ROM