We have implemented the component parts of a basic game engine. We can do so much more. Of course, a modern mobile game will have a lot more going on than in ours. How will we handle collisions when there are lots more game objects? Couldn't we tighten up our class hierarchy a bit, as there were lots of similarities between our PlayerShip and EnemyShip classes? How can we add complex internal character animations without confusing the structure of our code, and what if we want smart enemies, enemies who can actually think?

We need realistic backgrounds, side objectives, power-ups, and pick-ups. We want a game world with real-world coordinates that map back accurately regardless of the resolution of the screen.

We need a smarter game loop that runs the game at the same speed regardless of the CPU it is being processed on. Most of all, what we really need, more than any of these things, is a dirty big machine gun. Let's build a classic platform game.