Playing with #godot for the first time, and accidentally set some bullets to be rigid objects in the 2D physics engine rather than 2D 'areas'.

Which was actually hilarious, because rather than making the enemies dissappear like a normal boring game, the 1kg bullets travelling at several meters per second effective speed smacked the enemies off the screen spinning violently.

I'm sort of convinced that a huge number of action game mechanics start as 'happy accidents' like this.