Portal: Prelude, as its name states it, is an unofficial prequel to the game Portal. Its story revolves around the pre-GlaDOS epoch, even before she was plugged in. At this time, test subjects were monitored by real Aperture Science employees, whose work was tedious, lengthy and repetitive. This is why they decided to build a great artificial intelligence that could both replace them in these difficult tasks, and also take responsibility for many other tasks within the complex and compete with Black Mesa's superiority. All employees of the Aperture Science complex are now eagerly awaiting GlaDOS. Maybe even a little too eagerly, as the upcoming events will tell... This game is totally free. It offers a bit more gameplay hours than the original Portal, with 8 chapters, 19 test chambers, 48 challenges, 6 advanced maps, a brand new storyline and more than 400 lines of english speech with dozens of subtitles translations.
Full release of Portal: Prelude HD, featuring all-new textures.
Unzip and Play. All the files needed to make Portal: Prelude run.
This new version is shipped with the 1.1.5 build. Also, there was so much changes to the game files that it's pretty much useless to release a cumulative patch. It would be nearly as big as the complete installer itself. Please note that there's nothing worth redownloading the whole mod again if you already downloaded it, as it's mostly graphical improvements, optimizations and minor bug fixes.