Originally posted by: trelin
Freespace 1 and 2 are definitely not abandonware/free. Only the sourcecode was made available, the game data (graphics, movies, etc) were not. To play you still need to purchase a copy of the originals. Freespace 1 is also not abandonware, but the missions themselves have been ported to use the FS2 engine and data (similar to a mod) which kind of sidesteps that issue.
Once you have a working Freespace 2 install, the easiest enhancement is through the "Freespace Open Installer". Essentially it simplifies tracking down a host of improvements and addons to the base FS2 engine. Just install FS2, update if necessary and run the exe at fsoinstaller.com. That includes the improved engine with updated maps/models to utilize the new features. It also provides "Freespace Port", which is the Freespace 1 mission ported to the updated fsopen engine, and "Silent Threat: Reborn", an updated (many would say improved) version of the original "Silent Threat" FS1 addon.
WARNING: the fsoinstaller downloads ~
3.5GB
To play the mods like "Freespace Port" use the fsopen "Launcher.exe" installed in the base directory. Do "Select Mod", then select the "fsport" folder in the base install directory. That will even change the startup movie so you'll get the complete storyline.
Freespace Installer:
http://www.fsoinstaller.com/
Freespace Open Project:
http://scp.indiegames.us/
Freespace Open Forums:
http://www.hard-light.net/forums/?cat=37
Freespace Port:
http://fsport.hard-light.net/website/
(Disclaimer: I'm quite literally just going through the fsoinstaller process for the first time as I write this, I apologize if I've left anything out.)