Progress Report

I had two more afternoons and evenings to work on this and it's coming along nicely!

I changed the music (now there are three music pieces that can be cycled using the "M" keyboard shortcut) and added more explosion types, plus a new enemy type. Cracks are also appearing on more of the Asteroid types (note: The graphics package I'm using contains the 'crack' versions for all asteroids, but I have to manually copy/paste those sub-images to the sprites, so I'm only doing it when 'necessary'. Eventually, all asteroids will show cracks as their damage progresses.)

The big gameplay nuisance was having to return back to some base to restock ammo, plus the difficulty of stopping on a base once there. So I added a "quick stop" key (SPACE), and an ability to teleport back to base at any point. This feels really good and allows for some new strategies. 

Funny issue was that when I first implemented this 'teleport back', I forgot to teleport a Base upgrade that the ship was dragging as well, so it would slowly fly from its original position towards the player, who would be wondering why they can't pick any new upgrades :-)

Also managed to add Scoring (you get points for killing aliens, shattering asteroids, and for wiping all pieces of a Core asteroid before the next wave spawns). Once you get eliminated, you get a Game Over screen listing your score.

Difficulty is also now ramping up all the time. At first, the time between 'waves' is getting shorter (by few seconds every wave), until it reaches 30 seconds. At that point, the number of Core asteroids that spawn at the same time starts slowly increasing (by 0.3 per wave, so you get few times 2 asteroids, then few times 3 etc.)

I've uploaded a revised Game Design Document if you'd like to see my thinking. I did a little brainstorming about possible change of name, which was ultimately successful.