Revisions thumb|upright=1.2|Three case styles were used: C64 (top, 1982), C64C (1986, middle) and C64G (1987, bottom). Commodore made many changes to the C64's hardware, sometimes introducing compatibility issues. The computer's rapid development and Commodore and Jack Tramiel's focus on cost-cutting instead of product testing resulted in several defects which caused developers like Epyx to complain and required many revisions; Charpentier said that "not coming a little close to quality" was one of the company's mistakes.
Revisions thumb|upright=12|Three case styles were used C64 (top 1982) C64C (1986 middle) and C64G (1987 bottom) Commodore made many changes to the C64's hardware sometimes introducing compatibility issues The computer's rapid development and Commodore and Jack Tramiel's focus on cost-cutting instead of product testing resulted in several defects which caused developers like Epyx to complain and required many revisions; Charpentier said that "not coming a little close to quality" was one of the company's mistakes