What operating system was needed for 2D games?
CREATE TABLE table_name_91 (required_os VARCHAR, type VARCHAR)
SELECT required_os FROM table_name_91 WHERE type = "2d"
### Context: CREATE TABLE table_name_91 (required_os VARCHAR, type VARCHAR) ### Question: What operating system was needed for 2D games? ### Answer: SELECT required_os FROM table_name_91 WHERE type = "2d"