An irritating quiz, to say the least. The shortage and surplus questions should accept "excess demand/supply" or "over/underproduction". The question on government-controlled economies was the most annoying; I tried: central, planned, control, communist, marxist, socialist, central economy, planned economy, control economy, communism, marxism, socialism, and finally centrally planned economy. It's absolutely absurd that you have to type in two synonymous answers to gain credit, especially given no guidance as to how many answers are expected.
Needs yellow boxes. Also needs more acceptable answer options. For example: "Central Planning" was not accepted as an answer even though that is a common way of describing it.