1) The crusader is supposed to shoot 3 missiles (in a triangular formation with a pyramid scheme) from long range. In Vavoom, it seems to shoot 2.
2) The missiles shot from the Crusader are supposed to have transparent smoke just like the missile launcher your character has.
3) The Crusader is supposed to shoot the flame thrower in short range (I'm not sure how far exactly.. but mostly short range) and missiles within long range. In Vavoom, there is a tendency to fire the flamethrower from short-mid (and slightly long) range distances and less apt to fire from long range.