Game is getting closed in the background!?

Isnt that all controlled by the os? And as all Android manufacturers seem to have their own custom android it means that changes from phone to phone.

Okay, but how can other games manage to stay open then? What exactly is the difference to a Corona game?

OS automatically closes apps as it runs low of memory. Corona apps dont seem to have running background services and they are games so prolly bigger memory users than average apps so closing them frees much memory and with no services running closing em wont cause issues. But like really Ive never heard that apps must save state. Can anyone tell me one game that does?