GZDoom is a source port for the modern era, supporting current hardware and operating systems and sporting a vast array of user options. Make Doom your own again!In addition to Doom, GZDoom supports Heretic, Hexen, Strife, Chex Quest, and fan-created games like Harmony and Hacx. Meet the entire idTech 1 family!Experience mind-bending user-created mods, made possible by ZDoom's advanced mapping features and the new ZScript language. Or make a mod of your own!Can play all Doom engine games, including Ultimate Doom, Doom II, Heretic, Hexen, Strife, and moreSupports all the editing features of Hexen. (ACS, hubs, new map format, etc.)Supports most of the Boom editing featuresFeatures complete translations of Doom, Heretic, Hexen, Strife and other games into over ten different languages with Unicode support for Latin, Cyrillic, and Hangul so farAll Doom limits are goneSeveral softsynths for MUS and MIDI playback, including an OPL softsynth for an authentic “oldschool” flavorHigh resolutionsQuake-style console and key bindingsCrosshairsFree look (look up/down)Jumping, crouching, swimming, and flyingUp to 8 player network games using UDP/IP, including team-based gameplaySupport for the Bloodbath announcer from the classic Monolith game BloodWalk over/under monsters and other thingsCommercial data files are required to run the supported games. For more info about all supported games and their data files, see: Help -&gt; List of supported games.With Flatpak, all file-access is restricted to ~/.var/app/org.zdoom.GZDoom/.config/gzdoom for privacy reasons. You'll have to manually place your IWADs and PWADS there, or you should use an application like Flatseal to give GZDoom additional permissions.

GZDoom

Classic first-person-shooter engine for all classical Id games

Xonotic is a free and fast-paced first person shooter which combines addictive, arena-style gameplay with rapid movement and a wide array of weapons.Xonotic is easy to learn, but hard to master! Besides thrilling action for the casual player, the game also provides e-sport opportunities for those interested in its competitive aspects. From mapping contests and monthly quick cups to sponsored tournaments, Xonotic allows every e-sport enthusiast to participate in competitions hosted by its open-minded community.Features such as simple items, fully customizable configs and servers, a functioning anticheat system, the spectator mode, and the opportunity to watch and record games makes Xonotic attractive to competitive players.

Xonotic

Multiplayer, deathmatch oriented first person shooter

OpenSpades is a clone of Ace of Spades 0.75, which is a free online first-person shooter created by Ben Aksoy, featuring fully destructible terrain and plenty of game modes (including the well-known Capture the Flag) created by the community.Can connect to a vanilla/pyspades/pysnip serverUses OpenGL/AL for better experienceOpen source, and cross platform

OpenSpades

EDuke32 is a source port of Ken Silverman's Build Engine with support for Duke Nukem 3D, Ion Fury and Shadow Warrior (via VoidSW), among others.Features include:Modern OpenGL rendering with dynamically lighting and shadowsVoxel assetsEmulated OPL3, MIDI or OGG/FLAC soundtracksGamepad supportClassic software renderingEDuke32 comes with a map editors, Mapster32 and Wangulator, for creation of new levels and is free to use for non-commercial purposes.

EDuke32

EDuke32 is an awesome, free homebrew game engine

Zandronum is a multiplayer oriented port, based off Skulltag, for Doom and Doom II by id Software. Zandronum brings classic Doom into the 21st century, maintaining the essence of what has made Doom great for so many years and, at the same time, adding new features to modernize it, creating a fresh, fun new experience. Here's why you should kill your time with Zandronum, versus vanilla Doom:Client/server architecture: play and switch between games with easeSupports up to 64 playersWide array of gameplay modesCompetitive: Team DM, Duel, CTF, Possession, LMS, Terminator, SkulltagCooperative: Survival, Invasion (or both!)Modifiers, like Instagib and Buckshot, can be used to spice up any gameModern and beautifulSupport for large number of ZDoom and GZDoom modsChoose between GZDoom's OpenGL renderer, or Doom's Software rendererUseful features like a console, Quake-style key bindings, freelooking, and jumpingSupport for many Doom engine based games including Heretic, Hexen, and StrifeSupports modern versions of Windows, Mac OS X, and LinuxIn some scenarios, commercial data files are required to run the supported games. In other cases, it's possibly to automatically use Freedoom as a drop-in replacement. This package comes bundled with Doomseeker for easy installation and server browsing.

Zandronum

Leading the way in newschool multiplayer Doom online

Red Eclipse is a fun-filled new take on the first person arena shooter, built as a total conversion of Cube Engine 2, which lends itself toward a balanced gameplay, with a general theme of agility in a variety of environments.Cross-platform multiplayerFeatures parkour, impulse boosts, dashing, and other tricksFavourite gamemodes with an array of mutators and variablesBuiltin editor lets you create your own maps cooperatively online

Red Eclipse

First-person shooter with agile gameplay and built-in editor

Yamagi Quake II is an alternative client for id Software's Quake II. Our goal is to provide the best Quake II experience possible, we strive to preserve the gameplay as it was back in 1997. Thus we aim mostly for bug fixes, stability and gentle enhancements were appropriate. Yamagi Quake II has a lot of unique features. The most notables ones are:A modern OpenGL 3.2 renderer, providing a greatly enhanced look and feel. The original OpenGL 1.4 and even the Software renderers are still supported. Both 3D accelerated renderers support anisotropic filtering and multisampling anti aliasing.Full support for widescreen displays and arbitrary resolutions. The HUD can be scaled to be readable on high resolutions.Support for surround sound, from stereo up to 7.1 channels and even HRTF. The background music can be played from OGG/Vorbis files, a CD drive is no longer necessary.A rewritten savegame system. Yamagi Quake II savegames are completely reliable and backward compatible between releases as long as the principle architecture stays the same.Highly precise timings. For example, on a flat panel display with a 59.95 hertz refresh rate and vertical synchronisation (VSync) enabled Yamagi Quake II is running at exactly 59.95 frames per second.In comparison with the original client over 1.500 bugs were fixed. The Yamagi Quake II client is very well tested and stable. The dedicated server is able to run for weeks without a single restart. Last but not least the code is fully 64 bit clean and highly portable.Commercial data files are required to run the supported game. These can be aquired though a multitude of sources. See the manual for more info on this.

Yamagi Quake II

Yamagi Quake II is an alternative client for id Software's Quake II

World War II rages and nations fall. SS head Himmler has Hitler's full backing to twist science and the occult into an army capable of annihilating the Allies once and for all. Battling alone, you're on an intense mission to pierce the black heart of the Third Reich and stop Himmler -- or die trying.The intent of this project is to provide a baseline RTCW which may be used for further development and fun. The map editor and associated compiling tools are not included. We suggest you use a modern copy of GtkRadiant. Some of the major features currently implemented are:SDL backendOpenAL sound API support (multiple speaker support and better sound quality)Full x86_64 supportAVI video capture of demosMuch improved console autocompletion &amp; Persistent console historyColorized terminal outputMuch improved QVM toolsMany, many bug fixesCommercial data files are required to run the supported games. These can be aquired though a multitude of sources. See the manual for more info on this.

IO Return to Castle Wolfenstein

Game engine for Return to Castle Wolfenstein

Nexuiz Classic is a fast-paced 3D deathmatch game with high-end and complex graphics effects. It is intended to be played over the Internet or over a local network. Several different game types, such as classic deathmatch, team deathmatch and capture the flag are available. It also supports a single-player mode and playing against the computer.The game brings deathmatch back to the basics, with perfect weapon balancing and fast paced action, keeping itself away from the current trend of realistic shooters.This game was originally released as "Nexuiz", but is now referred to as "Nexuiz Classic" since the Nexuiz name was re-used for a non-free game for consoles.

Nexuiz Classic

Tremulous is a free, open source game that blends a team based FPS with elements of an RTS.Players can choose from 2 unique races, aliens and humans. Players on both teams are able to build working structures in-game like an RTS.

Tremulous

Aliens vs Humans, First Person Shooter game with elements of Real Time Strategy

Dhewm 3 is a source port of the original Doom 3 (not Doom 3 BFG, for that you may want to try RBDoom3BFG). It's known to work on Windows, Linux, macOS, FreeBSD, OpenBSD and AROS, but it should work on (or be easily portable to) any system that supports OpenGL 1.4 with ARB shaders, SDL and OpenAL.Compared to the original version of Doom 3, Dhewm 3 has many bugfixes, supports EAX-like sound effects on all operating systems and hardware (via OpenAL Softs EFX support), has much better support for widescreen resolutions and has 64bit support.It only supports old Mods if they either don't require their own game DLL or have been ported to Dhewm 3 - see the Mods page for more information.Mod-binaries who are supported, are bundled with Dhewm 3. External data is still required.Note that while the Doom 3 source code has been released under GPL, you still need to legally own the game and provide Dhewm 3 the game data to play. See the How to Install section for more information.

Dhewm 3

Welcome to the home of ezQuake, a modern QuakeWorld client focused on competitive online play. Combining the features of modern QuakeWorld® clients, ezQuake makes QuakeWorld® easier to start and play. The immortal first person shooter Quake® in a brand new skin with superb graphics and extremely fast gameplay.Modern Graphics: Particle explosions, shaft beam, gunshots, nails, rocket and grenade trails, blood, and others, MD3 models, fog, water effects, killing spree messages, rainModern competitive gaming features: Fullbright skins, forcing team/enemy colors, advanced weapon handling, teamplay messages, auto game recording, automated screenshots and console loggingGraphics customization: Customize your HUD, colors of walls and liquids, turn superfluous graphics effects off, change world textures, crosshair, sky picture, console background, game fontIndependent Physics: Get the smoothest experience possible without being limited by server or network settingsIntegrated Server Browser: Easy searching and filtering of online serversEnhanced demo/QTV playback: View recorded games from multiple points of view, watch action on radar, all player stats in a handy table, autotrack the strongest playerCommercial data files are required to run the supported games. These can be aquired though a multitude of sources. See the manual for more info on this.

ezQuake

a modern QuakeWorld client focused on competitive online play