When I reworked the weapon firing code to support multiple weapons, I accidentally switched two of the arguments. This resulted in a bug where one of the other ships (the giant smiley) fired a barrage of seeker missiles when the secondary fire button is pressed. When I say a barrage, I mean two missiles every frame. So, I was able to sustain >50fps with >300 missiles onscreen, all doing the seeking calculations. I love fast computers.
It looks hilarious though, swarms of missiles heading straight for you, and getting battered around by them. If I ever write some proper movie generation code for spacegame, I'll post a video of it.