Part I is done* and up!
Dark Interval: Part I includes four new chapters - the Prologue, revamped Welcome to City 17, Manhack Arcade, and Kleiner's Lab. Part I contains total of 11 levels.
Part I requires installed copy of Source SDK Base 2013 Singleplayer. It does not require HL2, nor the Episodes. Source SDK Base 2013 Singleplayer is a free platform, available in the 'Tools' section of your Steam Library.
To download Dark Interval: Part I, go to the Files section here and select the newest download.
Once downloaded, use 7zip to unpack the archive.
Place the 'darkinterval-release' folder in your \sourcemods\ folder.
Enable '-upcoming' beta option for Source SDK Base 2013 Singleplayer. This can be done via Tools->Source SDK Base 2013 Singleplayer->Settings.
Everything should be ready - now launch the mod.
Review and share!
*Await further updates - we plan on expanding and supporting Dark Interval: Part I via post-release patches.
Also, we are aware that the dialogue sequences in the mod lack lip synching. This is a global issue in Source SDK, and, at this time, cannot be easily fixed. We're looking into possible solutions.