That is correct, however, only 3 bullets are allowed to be on the screen at once.
CAD's demo fight which gets Kraid down to 44 hp gets into a pattern where Kraid takes 1 point of damage every 4 frames. It is on the frame where Kraid takes damage that the animation counter for his feet advances by 1. Hence, while he is being fired at every frame, he is still able to act at 1/4 speed relative to Samus.
Kraid's bullets do not appear to fire in concert with his animation counter, but I have not found an independent counter that controls their action.
Incidentally, missiles do 4 points damage, but beams only 1. The existing 100% run fires missiles at Kraid, but only hits him with the first 1; the rest of the missile "hits" are ignored and he only takes 1 point damage at a time (beacause the beam is also being fired)...this could probably be improved in a 100% improvement.
EDIT: A couple of interesting discoveries...
1. Firing every frame confers no advantage on bosses; it only increases lag. With proper pixel alignment and timing, one shot every 4th frame suffices to maximally stun Kraid.
2. Kraid's projectiles are controlled by counters at $2d, $429 and $42d. $2d is the frame counter and can be manipulated via pause/unpause; at multiples of 16 frames Kraid has a chance of firing. $429 and $42d are animation counters, NOT affected by pausing, and count down from 156 and 256 when Kraid starts moving. When they reach values of 1 and 100, Kraid will fire no matter what the frame count is.
3. So, a definite no go on killing Kraid without dodging his projectiles. I cut about 1/2 second off Hero's Kraid fight by minimizing the time in the air dodging.
4. In case this isn't widely known, the partially commented source code is available:
http://mdb.classicgaming.gamespy.com/m1/m1source.txt
