Impulses

Normally Quake ignores impulse commands while you're in the middle
of an attack animation (for most weapons) or while you're attacking at
all (for the nail and lightning guns). This makes things look a little
nicer (for the player, because of the weapon animation, and from the
outside, because of the player animation). It causes impulse commands
to be lost if more than one is sent to the game before it checks for
them, though (only the last one received works). I've changed it so
that the game always pays attention to impulse commands, even if you're
in the middle of attacking.

For most people, the most important thing this will affect is that
you can use your rune even while attacking. Eg, if you shoot a
rocket and then activate the shield rune, the shield will come up
immediately rather than waiting until the rocket animation finishes.

Additionally, if you're using a complex binding scheme to do client
side switch firing, it will generally work better because the only
time an impulse command is lost is when two are sent in the same
game tick. Use the "wait" command to make sure the impulses each
arrive in a different tick.