this is a complete 5 stage, space shooter game that exploits Box2D Physics: forces, (revolute) joints, sprite raycast, ecc.
You pilot a space rocket against killer satellites, revoluting space spheres (using joints), meteorites, death star-like boss, and do slalom through still space spheres, followed by meteorite. There is a black hole at the center of the screen, that attracts everything with gravity force. Deadly X-rays come from the black hole and the space rocket must avoid them too. The ship can fire missiles against the enemies. The missile can destroy enemies on stage 1,2 and 4, change trajectory of asteroid on stage 3, hit the boss on stage 5. You can use the rocket to move, but beware of the fuel rapidly exhausting when used.
The app is available both for Windows platform (using a joystick) or for Android, using the virtual buttons at the bottom of the screen. My family testers (my sons) appreciated the game. Since at level 3 it is very difficult, I put a "continue" feature in order to progress through levels. High score is make persistent by writing on file.
Here are some screenshots.