Project Deathlok was a HYDRA project conducted in cooperation with the Cybertek Corporation. It was one of HYDRA's several attempts to create Super Soldiers.
In 1990, after being affected by the explosion of an IED in Sarajevo, John Garrett was brought in by HYDRA as the first test subject of Cybertek's Project Deathlok. At first, the program was able to save Garrett's life. However, by 2014, Garrett's organs started to fail and the only thing keeping him alive were the bio-mechanical parts. This forced him to use the Centipede Project's Serum and manipulate Coulson to finding the GH.325 cure.
The second known test subject was Michael Peterson in 2013. Following his apparent death, Peterson was then outfitted with an eye implant and then placed in stasis. Peterson was then taken to a villa in Italy where he was given a Prosthetic Leg. Following that, Peterson was then given a Forearm Rocket Launcher.
After being freed by Garrett and HYDRA, Ian Quinn attempted to convince members of the United States Armed Forces to give Cybertek a contract to build thousands of Deathlok Soldiers for use in military operations. Quinn brought General Jacobs, Admiral Jolnes, and other government officials to the Cybertek Manufacturing Facility in New Mexico for a tour.
He showed them the only known prototype of the machine that built the Deathlok soldiers. His tour was interrupted by Garrett who killed Jacobs and imprisoned the rest of the officials before a battle with Coulson's Team broke out. The machine was used by Garrett to repair himself after he lost the battle when Mike Peterson nearly killed him; however, mere moments after he was rebuilt, Garrett was killed by Coulson.