There is one more attack pattern. I have redesigned the attack system so that the enemies do NOT have their clocks auto-incremented (though they can call a function in their update code to do so if they really need it). This is so I can use the clock to store states instead. The new attackers slide in from the top-right, move down until they are level with the player then slide right again.
One peculiarity of gameplay in Fire Track is that you are permanently firing. You can never let go of the fire button. Also, the enemy ships do not fire at you - they just try to crash in to you.
I ran out of room. The game refused to compile. So, with a bit of tweaking in the map editor and a rewritten scrolling routine, I have doubled the amount of free space (without the music, about 10000 bytes are free). I'm using RLE compression on each 20 bytes of the level. If I get even tighter for space, I could probably pack the 8 bit level bytes into 6 bits.
Here's an awful sprite of an explosion. It looks really ropey, but it's as close as I can get to the authentic Fire Track (ship) explosions. I don't know how good it'll look in action!