The food isn't fancy, but it's certainly an 'improvement over' what we're served at school.
His cooking needs 'improvement'. = There's still 'room for improvement' in his cooking.
The editor made some 'improvements' to/in the article before it was printed.
(..) An employee is killed and your first action as CEO, you covered it up! No, you covered it up and then you buried him in the bug house using my name. Ravenscroft is a time ? institution devoted to mental improvement. You're experimenting on people in there. Progress has its stepping stones. fired. (..)2014 The Amazing Spider-Man 2