I tinkered with this more yesterday, and i found that the only flag you really need to change is the +Radius one. yup
put +Radius to 1.0, and the missile or laser (it works wit primaries too!) will fire downward at what seems a 10 degree angle, so rightfully, 18 should make the weapon fire backwards, but nope. putting the +Radius from 1 to 9 gives it firing of 10 to 90 degree firing angles, until it is firing straight down, i think. but anything above 9 just makes it fire straight down at higher speeds. oh, and if you change the time compression the weapon fires differently too. buncha weird crap!
also, negative numbers work too, you can fire upwards if you want.
... this is really similar to something else. try this, set a ship to fly at say... 10 million mps when you hit the after burners, start a single player mission, set invulnerability on wit cheats, then fly out REALLY far. the game gets all screwy when you do this (much like in metroid prime, when you jump out of the play area and fall through the floor for 10 minutes, the game gets screwy). after dis, fire some weapons, lasers seem to fly off in random direction, changing direction of the time compression is changed.
and one more thing, any weapon yo udo this to, the firing downward or at angles thing, it will fire normal the first few seconds of the game, then it will fire at the angle for the rest of the game.