The problems have 'retarded' the progress of the program.
mentally 'retarded'
(..) We'll see more or less? It's... - What the hell? - What? - No tongue. I promise. - You're retarded. Can't you go faster? I can't run in these conditions. - I'm at the maximum. - The maximum... it's way too slow. Nine miles per hour. Suits him? (..)2011 The Intouchables