The conditions for games to fulfill for them to be on this list:
*must be some type of FPS-RTS hybrid asymmetric team based game; teams have a base to defend and the goal is to attack the enemy base spawn structures and maybe eliminate surviving enemy players
*One team specialises in melee and manoeuvring combat while the other specialises in ranged weapons.
*The general trend is that Meleeing team typically are some form of alien life form but don't necessarily have to be, thus AvH (Aliens vs Humans). They also seem to stem from Quake2's Gloom which also has some inspiration from the original Quake World's Team Fortress game
Also See: https://sites.google.com/site/zdrytchx/home/current-tremulous-related-developement-list
If you are looking for Gameplay Differences, see this reddit thing, though it is a little bit outdated: https://www.reddit.com/r/ns2/comments/4bsws2/the_ultimate_comparison_between_natural_selection/
Excluded: Client Enhancements and unofficial modifications (such as Tremfusion for 1.1, Faction for NS2 etc.)
Note: You need a screen at least 1280 pixels wide to view to full table
Also Sorry about the table. Google is being a bitch and won't let me make it thinner. TODO/Fix
Legend:
??? = No clue
?? = Needs Confirmation / Unsure / No Information Available / Unknown
? = Partial Details known for sure
Brief Summary:
In order by date released:
1990s
Gloom = Gloom 1.3, Quake 2 Mod, Developed by Team Reaction ((C) 1998-2001 David Wallin and Jean-francois Leclerc) | 1998
2000s
NS1 = Natural Selection version 3.2 | Half Life mod | Developed by Unknown Worlds Entertainment (UWE) | GoldSrc engine | 2000-2007 (?) Publicly released 2002. Last patch 2012. Gamelogic source publicly released 2014.
Trem Q3 = Tremulous 1.0 | Quake 3 Modification | Developed by Darklegion Development (GPL 2000-2016, Tim Angus) | 2000-2005
Trem 1.1 = Tremulous 1.1 | ioQuake3 engine | Standalone, Darlegion Development | 2005-2006, Official repository Community Contribution 2006-2008 (where it turned into 1.2GPP?)
Trem 1.2GPP = Tremulous 1.2 Gameplay Preview, | Trem 1.1 Mod | 2009-2011, (2008-2009 as a 1.1 compatible mod). Does not include protocol 71 version which extends to 2017 as it was not publically released, even if GrangerHub's team forked off the project.
2010s
TremZ = TremZ | Successor to Tremulous | OpenWolf engine (OW) | Cancelled Project | Developed by the Unvanquished team. OW engine still under works. | 2011
UNV = Unvanquished | Standalone, Forked off TremZ, Daemon Engine (OpenWolf fork) | Being developed by the Unvanquished team (Those who left TremZ) | 2012
NS2 = Natural Selection 2 | Commercial Successor to NS1 | Standalone | Developed by UWE | Spark Engine | 2012
T2 = Tremulous2 | Rotacak and AAAGames | Unreal Engine 3 | 2014? announced, project cancelled, well, but the Murnatan project was brought out from it
NS2C = NS2 Combat | or Natural Selection 2 Combat | Standalone | Developed by Faultline Games; Licensed under UWE | Spark Engine | 2014
Trem 1.3 = Tremulous 1.3 | Forked off Tremulous GPP but accepts Protocol 69-71 | OpenGL 2.1, 3.3 may have been planned | GrangerHub.com community made | 2017
MUR = Murnatan | formally known as T2 but has different alien assets | Unreal Engine 4 | Rotacak and AAAGames | Alpha released 2018. Lacks funding but is playable and development continues. Available on Steam on the Free-to-Play model
*Trem 1.3 isn't exactly a true standalone, because it's mostly just two seperate projects, one being basically a somewhat unappreciated gameplay mod on protocol 71 and the other being a multi-protocol client.
Not Yet Released:
Trem GPP (1.2) = Tremulous GPP | Version currently available on Github (Protocol 71) | Mentions to be Released S00N™ on "Thursday" (ambiguous, undefined which Thursday specifically). Considering it was announced in like 2008, chances are it won't be released anytime soon as a standalone.
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