I didn't make it!
From Valve Developer Community
 The concept:
Third Wave is set in an alternate reality of the Half-Life universe, it takes place in a secret research facility in Cheyenne Mountain much like Black Mesa, but specialized in a lot of different scientific areas including cybernetics/genetics/psionics/space-time manipulation and advanced warfare. It was here the first prototype of the hyperdimensional resonator was developed. The game takes place before the events of Half-Life 1. The player is Jacob Walkins, a young employee working in the administrative sector of the facility. When explosions and alarms are heard, he receives a video message from one of the lower facilities, warning them to get out while still can, explaining armed men are executing everyone in the lower sections. Afraid of the approaching danger he and his colleagues must try to disable the lockdown of the sector. A rmed with only one gun and a flashlight, they are off to find the service station. However strange creatures suddenly attack them and it seems all hope is lost as Jake loses consciousness. He wakes up in one of the restricted laboratories on his sector. Some security guards found Jake lying next to his dead co-workers, bleeding to death with his left arm ripped off, luckily the scientists of the lab managed to save him by giving him prototypes of cybernetic technology, including a new arm and advanced armored vest. It soon becomes apparent that Combine forces were behind the attack, raiding the facility in order to steal the advanced technology. It is now up to Jake to try and escape. But soon he learns the terrible truth behind the plans of the combine and decides to fight back.  Features:
• Cybernetic arm can be charged with energy to destroy almost anything • Different upgrade modules are available for the vest ranging from power enhancers to psionic and teleporter modules • Vest and some weapons can be programmed by typing code in the integrated arm-computer or by finding software modules • Fully functional, usable computer terminals and other electronics systems • Non-lineair plot • Fully interactive playing environment • Some weapons interact with the Nano Armored Vest • Upgradeable weapons • Experience system for weapon accuracy/strength etc... • Time-travel to locations of HL1 and 2 and change the future! • Completely new arsenal of powerful weaponry including never seen before high-tech weapons
The idea for this project started about 7 years ago as a mod for the original Half-Life under the project name of HL:SEPARATION, however due to other obligations the team fell apart, with the mod still being in an early alpha stage. We pitched the idea to Sierra and they thought it was very interesting and had potential, they invited us to show the project once we had completed it. But unfortunately it never came to that. However now with the advanced Source Engine my hope in realizing this idea is restored, and we will need all the help we can get.  Needed:
• CG Artists • 3D Artists • Mappers • Voice Actors • Programmers • Texture Artists
If you like the concept, and you are willing to help realize this idea, please contact me at [email]firstname.lastname@example.org[/email]