heXon is a free and open source twin-stick-shooter created using the Urho3D game engine.
To score high you must fly well, avoiding the Notyous and destroying them with your Whack-o-Slack blast battery. Your firepower can be increased by collecting five apples. Picking up five hearts in a row will charge your shield. All edges of the hexagonal arena are connected to its opposite like portals, making for a puzzlingly dangerous playing field that might take some experience to wrap your head around.