D-DEF is a bullet hell-style game inspired by an event in May 1940 where British soldiers planned to escape from the small French town of Dunkirk to London. The newspaper "The Sun" in the United Kingdom marks this moment as iconic in the Second World War since the allies could replace its strategy. The player will play the role of one of the submarines that will help in the rescue of the ally forces’ soldiers. The submarine became heavily damaged during the fight and that is why it’s on the surface so the movement on the screen, shooting and receiving shots will cause the energy to decrease.
The goal is to shoot down as many planes as possible and you make the best of the available energy to survive as long as possible.