The game is coming along. The ship can fire missiles now, which explode when they hit stuff, and the ship can be destroyed by flying into blocks that have a "fatal" attribute specified in the level file.
I got a pause system working, and this actually turned out to be far more complex than I expected. I sort of thought of things like this as trivial but it was a bit more involved than I thought.
Now when you press escape, the screen darkens a bit (via the diffuse colour), a "Paused" message appears in the middle of the screen and you can press "Q" to exit. Any sounds that are playing get paused as well, then restarted when you continue the game.
Don't really know where this is going since I'm making it up as I go along but I figure all I need is to add in some kind of thing to collect and some kind of way to exit a level once you've collected all the things, then a few different types of moving enemy, a title screen and a system for stepping though a variety of different levels and I've got myself a game.