Production was complete back in 2008, but (for unknown reasons) the film wasn't released until 2019 on Amazon Prime.
Agent Crush is an homage to the works of Gerry Anderson, a British television producer who used a technique called Supermarionation, combining realistic-looking puppet characters with intricate special effects and miniatures. One of the more overt references to Anderson's work is in the scene where Spanners and Crush fly to Spanners' lab, hidden beneath "Meddings Junk Yard" - a reference to Anderson's special effects master Derek Meddings.