There was a scene later cut out portraying Aaron as a diabetic. The shot showed him giving himself an insulin injection.
Shane Carruth stated that out of 80 minutes filmed for the movie, only 2 minutes were cut from the final product.
In the scene in which Abe-2 knocks out Abe-1 with nitrous oxide, the container he's holding is actually a rice cooker. Also, we see sleeping Abe's profile, but not standing Abe, because the latter was Shane Carruth standing in for David Sullivan.
The entire film was made for around $7000. Most of the money was spent on film stock.