[matheusmoreira]

> Does every game have an engine?

Yes.

Engines are essentially loops. There are many examples of engines in software and hardware. Processors, virtual machines, emulators: they are execution engines looping over instructions that they decode and execute. Game engines are the same: they loop over user input, logic and audivisual output. Every game will have this loop deep inside, no matter how it was programmed. It is essential to their operation.

Modern game engines are generalizations of that loop. People took the common functionality from successful games and separated it from the game-specific code.