Claustrophobia 1024 is a 2009 megawad, and the spiritual successor to Congestion 1024. Similarly to its predecessor, all of its levels are designed such that gameplay is restricted to an area of 1024×1024 map units. The project was led by Brett Harrell, began on July 10, 2008, and was released on June 17, 2009.
The project had two separate stages of development. In its alpha stage, the project was lead by Harrell and Death-Destiny. Although all of its maps were received in a short time, its development did not occur without controversy: Shortly after every map was submitted, on October 13, 2008, Death-Destiny began another sequel, Constriction 1024, even though the previous project had not been released yet, leading to accusations that he was being overly hasty. Soon after, it came to light that Death-Destiny had not shown Harrell any of the levels that were submitted, and furthermore had attempted to exert more control over the project than he was allowed to. The controversy that erupted from this led Death-Destiny to leave the Doom community. It was only then that Harrell received the submitted levels. After playtesting revealed that most of the finished product was subpar, the beta stage of development began, with most of the alpha-stage levels put aside until their quality was improved. Eventually, Joonas Äijälä began a side project for this purpose; some of the results of this project were used in Claustrophobia 1024, and the side project itself would later evolve into Claustrophobia 1024 2: The Mystery of Too Many Maps. Of the levels in the finished product, MAP07-12, MAP15, MAP18, MAP22-MAP24, and MAP26 originate from the alpha stage of development.
Although a significant portion of the soundtrack is derived from other sources, it includes original compositions by Eric Baker (The Green Herring), Paul Corfiatis, James Paddock (Jimmy), and Stuart Rynn (Forty-Two).