This list might just be survivor bias though - it only includes the projects where they didn’t get sued and taken down (either because the developer was ok with them, or because they strayed far enough into fair use).

There are clear counter examples - see Tengen vs Nintendo, Nintendo vs Palworld, Microsoft vs halo inspired games, Microsoft vs Minecraft clones. Most are settled out court. Examples that go to court tend to be from companies with budgets to fight, lots of projects will just get DMCA’d and won’t fight, or will back down after a legal letter.

Ultimately copyright and IP infringement is decided in the courts, and the rules aren’t entirely black and white.

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anthk 3 days ago | parent [-]

The actual list at https://osgameclones.com it's so huge that literally invalidates any point stated by HN commenters ignoring that, yes, Giana Sisters for the C64 was taken down but after that several Mario shareware clones existed for PC and a few years later we even got Supertux and, in the 2000's, Secret Maryo Chronicles which got renamed in order to avoid any issues with "Mario" as a TM, but the gameplay was 99% the same of Super Mario World.

On software recreating something propietary:

- FreeBSD, NetBSD, OpenBSD... vs AT&T Unix.

- GNU+Linux or GNU+Hurd against propietary Unix kernels.

- Coreutils+Findutils+Sharutils... every tool reimplemented being propietary.

- Bash, GAWK, GCC, binutils, Clisp, SBCL, GNU GCJ+Classpath, Red, FreePascal+Lazarus, GNUStep+WMaker, LessTif, EMWM+Motif vs Irix' Maxx Desktop (still propietary, and from the 90's) Gaim, AMSN, 7zip, Haxima+Nahzgul (and Ultima it's still being sold at GOG), Supertux2, Supertuxkart, ReTux (very Wario like), Hexoshi (Metroid), SMC (Super Mario World), Pingus (Lemmings), XMMS/Xine cloning WinAmp and maybe PowerDVD (Xine with skins), WordTsar for Wordstar, Nano for propietary Pico (and Alpine for propietary Pine), BSD vi and Amiga vim for maybe propietary vi under AT&T/commercial Unix, Lincity and Lincity-NG for Simcity, FreeCiv against Civilization (it can use both the OG Civ rules and their custom ones), Frozen Bubble (I think the level set it's from the Neo Geo release), KGoldrunner and such for Lode Runner, Kapman for Pacman, every BSD shipping Tetris and Boggle, GNU Octave for Matlab....

The list example for both software and games being just reimplementation/clones of propietary tools goes on an on. Even DOS had propietary clones which had to reimplement the same interface as MSDOS because if not the tools written for it would just crash. Same commands, same output, same formating tools, same memory layout, they ran the same DOS binaries and drivers...

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Closi 3 days ago | parent [-]

Giving a list of examples doesn’t mean this example is legal or would stand up in court.

Other than the fact that most of these are very different situations, but even if they were the same it is like saying “snorting coccaine is legal because I can give a list of celebrities that have done it and have not been arrested”

The examples that are similar - eg FreeCiv, imo probably survive because of the decisions and polices of the original publisher rather than some magical legal protection which allows you to make 1:1 copies without being sued.

TuxRacer isn’t really a copy of anything, and an OS or computer utility will likely be treated in a materially different way to a computer game by a court of law.

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anthk 3 days ago | parent [-]

No, your example can't stand out a simple analysis since both GNU and BSD reimplemented propietary UNIX without the original code, as the OpenTTD rewrite is. How come OpenTTD works on a G4 PowerPC arch if the original code was written in x86 assembly?

GNU AWK it's literally copycat of Unix AWK having all of the functionality of the original AWK without being bound to the original source. So is GCC vs any vendored Unix 'cc', 'ld' and 'as', where GNU GAS was the alternative.

Again, there's GNU Bash against Unix SH, with the same exact flags for interoperativity. Ditto with Alpine against Pine, or GNU Nano against Pico with the literal same interface, commands and layout. And these are older than TTD itself.

Should I go in? Lesstif against Motif. If you installed Lesstif tons of Motif stuff would work straightly as is, as XPDF did. Another one? XMMS. Once you skinned both the were the same.

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Closi 2 days ago | parent [-]

GNU != Transport Tycoon

Different types of media get treated differently by courts. If you repaint a painting 1:1 then you are liable to copyright. If you make a song that is too substantially similar you are liable to penalties. If your branding is too similar to the Oscar’s or Starbucks you are liable for infringement.

On the other hand if you reimplement Java the courts have decided that’s OK.

Different media are treated differently. A game and an OS kernel have different attributes in reality (even if technically they are both bundles of code - courts don’t always decide things on technical literalism, they often apply the spirit of the law, understanding if the application meets the original intent and precedents).

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anthk 2 days ago | parent [-]

Both OpenTTD and FreeDoom have identical gameplay to the originals but different assets. Also, the level layouts are different in both games as the scenarios are copyrighted, not the concept of the game themselves.

If anyone wrote custom cities, textures, scripts and so on with the OpenMW engine you are totally free to do so even if the result looks eerily similar to Morrowing but not being the same game at all, if any sharing a fantasy RPG setting and that's it.

Ditto with OpenArena being a total clone of the Quake3 Arena concept but with different levels and assets, and virtually it's the same game at a 99%. You can totally sell OpenArena or any new game reusing these assets if you comply with both the GPL and the CC license from the media.

Dave Gnukem it's an obvious Duke Nukem (pre-3D) clone and even if it can't play the original game, it can be trivially adapted to reuse the original textures and level sets in order to get a very close gameplay to the original. And yet no one sued them.

	▲	Closi a day ago \| parent [-]
		We are going around in circles. Of all the examples, Dave Gnukem quite obviously infringes the trademark. Again, just because no one sued them doesn't mean it's not succeptible to a trademark infringement claim if the IP owners wanted to sue. While I am aware they claim parody law exempts them, see the enforcement of other brands (e.g. Starbucks) and see how far that goes once it gets to court. But I don't think I'm going to convince you, and I don't think you are going to convince me, so I'll just disagree agreeably and this will be my last message.